


Every Part of the Animal

by Askance, komodobits



Category: Supernatural
Genre: Body Horror, Corpse Desecration, Gore, Hallucinations, M/M, Psychological Horror, Violence, canon-divergent, horrorfic, post-season 8
Language: English
Status: Completed
Published: 2017-07-06
Updated: 2017-07-06
Packaged: 2018-11-28 18:27:53
Rating: Mature
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 3
Words: 47,273
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11423637
Author URL: https://archiveofourown.org/users/Askance/pseuds/Askance, https://archiveofourown.org/users/komodobits/pseuds/komodobits
Summary: It’s their first case after the Trials, after Heaven has collapsed: playing back-up to another team of hunters taking out some werewolves in the mountains. It's a routine job, an easy job - at least until the radio goes silent. Sam, Dean, and Cas follow after, but the caves into which the hunters have vanished wind deeper and darker than they could have expected, and something is wrong. Cas can feel it. The Winchesters may not believe what he’s hearing, but there's something down here with them—and it's not the people they came here to find, and it's not the werewolves they've been tracking. It's something else, something older, something violent, and it knows they're here.





	1. Chapter 1

**Author's Note:**

> Based on the movie The Descent. This is a horrorfic; please take heed of content warnings!
> 
>  **Ginny:** Thank you to Askee, for endless reruns of The Descent and yelling about body horror cave shenanigans, and for allowing me to word-vomit nonsense and then somehow turning it into something worth reading; to Sonie, for betaing with a fine-tooth comb and picking out every single time when I used the same two goddamn similes; to everyone on Twitter, for putting up with my bullshit; and to Alex. The biggest and best gay we have: maker of tea, orderer of pizza, brainstormer of gruesome cave injuries, and tirelessly supportive horror-fic cheerleader. You’re alright, I guess.
> 
>  **Askance:** Thank you to Ginny, for understanding and accommodating my crippling writing insecurities, and never letting me get too down on myself, for being my partner in monster-stabbing, bone-breaking literary crime, and for being, as always, my dear, dear friend; to Sonie, our beta; and to the many, many mutual friends of ours on Twitter who have dealt with us far longer than most rational people would have. Cheers!

* * *

 

 

Three and a half hours of the uninterrupted sound of last year's late-December mid-Montana blizzard. Sam gave it to him.

 

            The file has been playing on a loop in Castiel's ears since before dawn. For a while he watched the mountain roads twisting and heaving and dipping, wet with a sheen of rain and unbelievably black, pooling under the Impala's front wheels, but after a while it started to make him feel sick, so he lay down across the back seat, watched the gentle rocking of the ceiling over his head, and turned the blizzard up as high as it would go. No sound of Sam and Dean gently murmuring in the front seat, no _whish_ of the car wheels on the wet asphalt. Only the wind and the snow in his head, and headlights passing occasionally over his face.

 

            Cas almost imagines, when he listens hard enough, that he can hear the individual flakes spinning and gathering in the clouds, hurtling downward. He tries to picture crystal formations in the dark, liminal space behind his eyelids. Each one its own.

 

            Falling and plummeting.

 

            Melting.

 

            He opens his eyes. He has picked up on where the recording ends and begins again, a sort of gentle hiccup in the flow of white noise.

 

            Cas turns his head on the seat. Sam and Dean are just shapes in the encroaching sunlight on the windshield. He squints, covers his eyes with his hand, turns his face back up to the roof again.

 

            The howl of the wind is incredible. He wonders if he'll ever witness a blizzard like this. The desperate, barren rustle of tree branches shifting across the surface of the recording, almost the surface of his skin—when he tunes into that, especially, goosebumps ripple over his arms and then fall again, as if in time.

 

            There are other files on his phone. Sam, of course, perpetually too-helpful, wanted him to have options. There’s white noise, pink noise, three different oceanscapes, even the long, drawn, ambient sound of a jet engine. But the blizzard is his favourite. It's comforting, in its way. It's _real—_ he can picture it, stalking down the prairie, freezing everything it touches.

 

            When Castiel thinks about death—and he does, these days—when he thinks about death, he thinks he'd like to freeze.

 

* * *

 

 

            Cas barely knows the car has stopped until the door against his feet opens and Dean leans in, motioning for him to pull out his headphones.

 

            He does, pushing up on his elbows, blinking in the sunlight. The bursts of real noise are always jarring after hours of playing Sam's files; he has to take a minute. Dean, of course, waits for a moment, and when he speaks his voice emerges slowly like molasses from the smog of birdsong and leaves and the car's winding rumble.

 

            “Up and at 'em, sleepyhead.”

 

            “I wasn't sleeping,” Cas says.

 

            Dean grins, reaches down and tugs a little on the shoelace of Cas' left boot. “Come on. We're here.”

 

            Then he disappears, into the thick mountain sunlight, and Cas looks down past his feet to the wide expanse of woods in which they've parked.

 

            He levers himself out slowly, feet-first, pausing a minute on the edge of the back seat with his boots planted in the mud to wind his headphone cord around his cell phone and tuck it safely away into his pocket. His ears are adjusting—not so much a crush of noise anymore.

 

            Below the car, a wide, flat expanse hewn out from the forest makes for some approximation of a parking lot. Ahead, and to all sides, are trees: peeling birchbark as far as he can see, in coils like white paper, black blemishes like misshapen eyes. A little ways away the earth lifts, vanishing up into peaks, crowned with white pine, and wind is blowing down through them, their branches waving and then still again. Up the hill, past the throat of the woods, is the squat concrete shape of the Birch Trails Motel, its sign unlit.

 

            Cas gets up, pulling down the corners of his borrowed jacket. Feels, like a paranoiac, for the phone in his pocket. His spine is aching.

 

            Back the way they came, the road gets wider, disappears into the woods, down the slow incline of the mountain. And up ahead, near the door, Dean's standing with his hands in his pockets, waiting for him.

 

            Cas shuts the car door, and then buys himself time by going to retrieve his duffel, slinging it over his shoulder, taking a moment to consider the contents of the trunk. The sawn-off shotgun that is now emphatically _his_ ; the untidy heap of rope and cable and carabiners that Pete and Sue didn't have room for in their backpacks; the paper bag where Cas knows his old trenchcoat is folded away, out of sight, waiting for a day when Cas feels he can bear to let it go.

 

            He slams the trunk shut and makes his way up the sloping mud to the motel.

 

            Sam leads the way in, his head ducked against the misting beginnings of rain, and Cas follows close behind. The teenager behind the front desk looks almost surprised to see them, her feet propped on the front desk, and she moves slowly to take their payment. Dean pays in cash - his card got declined at a gas station just north of Blacksburg, and he's not willing to risk it again in case it gets flagged as stolen - and he pays for three nights. Over the phone, Pete had said that he was confident in their intelligence, said that it wouldn't take more than a day or two to clear.

 

            The room itself is dark, all set out in faded 70s florals and heavy, dark fabric, the windows smeared and unpolished so that the bright mountain sunshine filters through slowly, dust stirring in the square of yellow light thrown across the threadbare carpet. There is a TV with bent rabbit-ears, and a fake gas fireplace set into one wall. Of the two beds, one has seen better days, sagging in the middle; there is a couch pressed into the far corner that Cas guesses is a fold-out.

 

            "Shotgun," Dean says, and he throws his duffel to land heavily on the first bed.

 

            Sam throws him a frown, and then turns back to Cas. "You want the other one?"

 

            "I'm okay."

 

            Sam looks back at Dean. "Happy?"

 

            Dean grins, wide and self-satisfied. "Yeah, I'd say so."

 

            Cas is used to their meaningless bickering over the small things on the road - who ate the last of the chips, who pays for gas, who goes in the shower first - and now their voices snag and tangle over one another as he stands for a moment quietly in the whirlpool of disorganised noise, not quite listening. He lets himself unfocus into the comforting buzz of their noise, the thumping of Sam starting to unpack, setting out his laptop and books and his gun. Cas crosses to the fireplace to twist the knob, maybe start it up, but there's no hiss of gas. It stays cold.

 

            He is engrossed in the white noise of Sam's voice, examining the gas knob, and so he startles when there is a hand, gentle, on the back of his neck.

 

            “Your tag,” Dean says. He tucks the back of Castiel's collar neatly in, and then smoothes the fabric of his jacket over his shoulders. “You goddamn barnyard animal.”

 

            Cas lifts his head to look back at him. “Thanks.”

 

            Dean's hand lingers too long on Cas' shoulder. His thumb idly traces the seam of Cas' jacket. “Come on. Let's get business outta the way. I wanna crack open those microwave lasagna and see the finest that Birch Trails cable has to offer."

 

            Behind him, Sam snorts a laugh, shaking his head.

 

            They set out the six-pack of beer to sweat on the coffee table, plastic bag of junk food waiting at the foot of the couch, the promise of a reward, as they settle to work. Sam unfolds the creased map of the mountains, tracing his fingertip over the four uneven lines scratched out in black pen where Sue had shown them their area of attack. The lines form a kind of crude trapezium that hooks the edges of the Cherokee National Forest; the dirt road on which the Birch Trails Motel sits is a curve between the first and second vertices, just a little off-centre.

 

            It was in Ripley that they first bumped into the Harrisons. Sue and Pete, their son, Kurt, young enough that his beard growth was patchy around his jaw, their battered pick-up truck. Sam and Dean knew them, by name more than by sight; Cas didn't know them at all. Friends of John's, he gathered, over beer and pool in a dive bar outside town. He sat quietly all night, waiting for the other shoe to drop, waiting for someone to mention the angels falling or the end of the world; but the Harrisons never said a word, about him, about the stretch of Sam's skin across his bones. Instead, they offered them a case.

 

            Pureblood werewolves in the mountains, terrorizing the mining towns. They were on their way to the National Forest to check out a cave system that seemed like a good lead, and they could use backup. Someone to man the radios and the maps and rescue services. It sounded simple; they talked it over in a back corner while Sue went out to the car and Pete showed Kurt how to properly sink a ball on the break. Cas mostly listened, nursing a beer that tasted of nothing, and when the brothers turned to ask if he was down, he shrugged, nodded. Anything, he'd thought, was better than driving aimlessly the way they had been after Sam had left the hospital, looking vaguely here and there into leads on fallen angels without pursuing them. It would be their first hunt since—well, since. It would be good to get back into some kind of game.

 

            Last night, when they'd stopped for gas, Dean had played Pete's last voicemail on speaker for them in the humid, cramped car. Their collective breath fogged over the phone’s screen in conjoining clouds.

 

            “Going in for recon in the morning. Texted you the details on our radio frequencies, numbers you need, all that. Make some headway into the system and see if we can find any evidence that it's inhabited. Animal bones, human bones, waste. If there's nothing there, we'll meet you back at the motel, move on. But if we do find something, well, uh, we'll meet you—we can all go in together to clear it out. We'll talk traps and bait and lures and things then, if we have to.”

 

            That was last night, long before dark. Now is the wait.

 

            Cas settles comfortably on the couch while Sam organises the research they have so far; Dean plucks three beers out of cardboard and passes them over. Cas sits back, picking idly at the wet label on his bottle with one hand as he shuffles with his other through their collection of mismatched autopsy reports.

 

            In the past month, four people have gone missing—each of them, for one reason or another, following one of the trails Sue marked out on the map. One body was recovered along the eastern-most trail, found with its chest cavity ripped open, heart still intact. The motel was identified as being a point of suspicion, but Pete and the others had already cleared it before Dean, Sam, and Cas appeared on the scene. The only remaining option was the caves, tucked into the shoulder of the mountain, uncharted but believed to be part of one tangled system below the surface, where werewolves could hide.

 

            Cas is stirred from his train of thought by Sam's voice:  “They checked in yet?"

 

            He looks over to see Dean with his phone, the blue glow of the screen light catching along his jaw in the gloom. "Nothing yet."

            Sam hums, faintly disapproving.

 

            "They said they'd get in touch tonight, once they got back to the edge of the preserve," Dean says, without looking up. Outside the rain-drenched sun is touching just below the tips of the trees, but not setting yet. "Night's still young. You found any history of similar disappearances?"

 

            Sam shakes his head. “No – it only started recently. Just after the angels—”

 

            He cuts himself off, clears his throat.

 

            “Yeah.”

 

            Dean lifts his head to look at him.

 

            Cas tips up his beer and drains it. He says, "I'm going to the bathroom."

 

            He has to duck his head under the door-frame, and then he steps into a bathroom that is maybe four feet square at best. There is one small window, high above the bath, and it lets a single narrow strip of blue light through the fogged glass. Cas shuts the door, pings the cord at the wall for the light. It flickers dimly to life, and Cas looks up at the bulb as it buzzes lethargically brighter, casting uncertain shadows across the rusted shower-head and the tiled wall.

 

            His shoulders pull up tense until the lightening bulb pushes the walls back to their respective corners, leaves him room to breathe. He runs the faucet fast enough that it sprays the tile and floor. He splashes his face with cold water.

 

            On the way out, he pauses for a long moment against the closed door. He reaches into his pocket and thumbs distractedly at his phone, scraping his nails over the ribs of his headphone cable, tangled unevenly around the case.

 

            Cas returns to find Dean and Sam distracted from their research.

 

            "—just saying, that doesn't necessarily mean anything."

 

            "Yeah, it does! I'm sorry—do you remember the last time we went up against a pack of pureblood werewolves?"

 

            Sam bristles. "Yeah, Dean, I remember—but I don't see how that's—"

 

            Cas steps carefully back into their midst, skirting Sam's duffel and picking his way over to where Dean's feet are propped up on the coffee table. He is nearly at his old stop when Dean commandeers his attention with a handful of his sweater, tugging at him. "Dude. You heard this one? Crawford, Nebraska. Sam was one-hundred—no, one thousand—percent confident in his assessment that we were—"

 

            Sam starts up an indignant noise of protest. "You know what, Dean," he cuts over, loud and disruptive, "I don't think Cas wants to hear this story—"

 

            "Oh no, Cas definitely wants to hear this story," Dean says, and he winks at Cas. "So Sam does his research, he says—much like today— _no way, there's no way that werewolves can organise their attacks, no way._ And then we go on and we're thinking it's not a werewolf—because, you know, Sammy is so goddamn sure—"

 

            "Like you've never had a hunch that went wrong, okay? Dean, you remember that rugaru you—"

 

            Dean extends a hand, palm flat, towards Sam. "Not right now, Sammy. The older brother is talking.” He clears his throat and goes on. “Sam is so goddamn sure, so naturally, we don't take the silver. We take the copper blade blessed with holy water, and a couple lead rounds just to be safe, and when we get to the warehouse—"

            Cas has heard the story before. He settles back against the couch cushions, looking between Sam and Dean as they laugh and squabble, as Sam stretches out a foot to kick at Dean's knees, with _shut the hell up, Dean_ in his mouth again and again, and Cas tunes out of the words to find the warm hum of Dean's voice, the alternating of Sam's laughter and his good-natured complaints.

 

            The conversation tilts and turns over itself into a buzzing murmur as they move from Sam's naivete to the rugaru case where Dean wound up strung up by his ankles in someone's basement, and Sam passes Cas another beer, once he has finished his first; Cas pulls himself from the noise long enough to thank him, and as the sound parts around him like the sea around a cresting rock, he finds the easy comfort of Dean's smile.

 

            Sam is laughing, loud and barking and inelegant, in a way that Cas hasn't heard in a long time; somewhere between his third and fourth beer, Dean's arm slips from the back of the couch and rests heavy, warm, along the line of Cas' shoulders. The conversation lulls and bubbles, and Dean doesn't take his arm away, and Cas tilts into him, warmth all along his thigh where his leg is pressed to Dean's. He fits snugly into Dean's side; he feels the steady rise and fall of Dean's breathing and is comforted by it.

 

            It is past midnight when the supply of beer is exhausted - past midnight when Sam starts to loll back in the armchair, when Dean starts to stifle a yawn into his knuckles, when Cas rolls back his shoulders to find a low ache curling in the small of his back from too long slouched over. Cas is what Dean calls _buzzed_ : not drunk, but rather comfortable, loose and warm. At his side, Dean is a little further along, leaning forwards in his seat to arrange his empties into a neat bowling-pin arrangement.

            "One game," Dean says. "I'll play you for tomorrow's pancake run."

 

            Sam raises his eyebrows. "Where the hell are we gonna get pancakes from?"

 

            Dean lifts his head, a grin tilting one corner of his mouth as he looks up at Sam. "You lose, you go find out."

 

            "That's not happening."

 

            Dean sits back in his seat, hands outstretched in a show of innocence. "What? You don't think you can take me?"

 

            "Come on, Dean. We gotta be up bright and early tomorrow in case they need us."

 

            Dean groans. He digs in his jeans for his phone, pulls it up, and brandishes it like a weapon at Sam.

 

            "No call. They still haven't checked in, therefore—"

 

            "Therefore something might have happened, and we're supposed to be their backup," Sam says pointedly. "We're getting up at six."

 

            "Six?" Dean echoes.

 

            "What did you think constituted 'bright and early'?"

 

            "Like, ten." Dean turns back to Cas. "You believe this shit?"

 

            At some point in the last three hours, Dean has raked his hands backwards through his hair, and it sticks up now at odd, improbable angles; his shirt is rumpled, his skin flushed and soft in the faltering light. Cas is caught on the delirious nearness of him, and when Dean raises his eyebrows, he can only say, "I'll make sure there's coffee."

 

            Dean rolls his eyes. "Well, at least you're on my team," he says, and he slaps a hand to Cas' shoulder, levering himself up onto his feet. Cas leans into the touch, into the fleeting warmth of Dean’s skin.

 

            They uncurl, slow and sleepy, to make their way to their respective beds, but Cas is not yet tired. He finds his way outside, instead, to the cracked sidewalk that traces the route between each motel door. Weeds and brown grass struggle up through the broken concrete, pushing at the edge where the packed dirt of the parking lot rises to meet it. Beyond the cars, the woods are dark and still, the autumn cold threading through narrowness of the trees. Voices rise and fall behind him, Sam and Dean still bickering over beds. The air is cold and clean, rain-sharp when Castiel breathes in.

 

            Then the door creaks open, throwing a long rectangle of soft yellow light across the wood and the leaf-moulding soil, and Sam comes out to settle on the walk beside Cas.

            "Hey," Sam says. "What're you doing out here?"

 

            Cas pushes his hands into the pockets of his hand-me-down jeans, having no real answer. "Too hot," he says, even though out here the autumn chill slips under his shirt, lifts goosebumps on his arms and neck.

 

            Sam stands beside him, arms folded over against the cold. "Cold enough out here." He looks over at Cas. "How are you feeling, anyway? Ready to get back out there?”

 

            Cas hesitates. He picks, with his fingernails, at the ragged hem of his hand-me-down jacket.

 

            Sam exhales. “Yeah,” he says. He looks out across the dark. “Me neither.”

 

            “I’m hardly getting back out there,” Cas says, after a beat. “I was never _out there_ to begin with. All this—it’s new to me.”

 

            “You’re getting pretty handy with that shotgun, though.”

 

            Cas tilts his head over. “Point and pull the trigger,” he says mildly. “It seems straight-forward.” Hours upon frustrating hours on the bunker’s underground shooting range means that Cas can hit a bull’s-eye from twenty feet now. He can’t hit a moving target for the life of him, but Dean has cheerfully offered to kneecap monsters and slow them down for him. _Keep those training wheels on a little longer._

 

            Sam laughs. “Yeah.”

 

            For a long moment, they are quiet together, looking out at where the mud slopes away into darkness, the shape of the cars hinted at by the dim lamp-light that spills out from the motel windows.  At his side, Sam stirs.

 

            Cas looks over. "Hm?"

 

            Sam glances at him. "What's up?"

 

            Cas frowns. "Sorry—nothing. I thought—"

 

            Shaking his head, Sam's face turns faintly disapproving. "You're still sleeping with the headphones in," he says. Not a question.

 

            Stubbornly, Cas turns away and does not answer.

 

            "You're gonna mess up your hearing. Seriously."

 

            "You'll have to speak up, Sam. I can't quite—"

 

            "Real funny. Look, I'm not saying don't listen to it. Just...dial it back a little. Maybe try going without it tonight. Maybe turn it off just before you fall asleep."

 

            Cas tilts his head over. "Maybe." He says it mostly to humour Sam; he doesn't see the point in trying to explain what the crushing silence is like for him.

 

            Behind them, the front door clatters open, and there is Dean with a frown, silhouetted by the soft yellow light from within. "The hell are you doing out here?" he asks. "It's cold. Thought we were getting up at the crack of dawn."

 

            "Yeah, yeah." Sam tilts his head over towards Dean and the room. "Come on, Cas. Gotta make waves tomorrow."

 

            Cas follows them in.

 

            In their absence, Dean has pulled out the couch, flapped a coarse pinstriped sheet over it, and laid out a squashed-looking pillow and scratchy wool blanket. Ahead of the couch, the coffee table is pulled askew towards the window to make space, and their bags are dumped unceremoniously in a heap in the middle of the room.

 

            Cas retrieves his bag, digs into his bag of toiletries, and then doubles back to where Dean is aggressively attempting to fluff a paper-thin pillow. He looks up as Cas approaches.

 

            "Hey," Dean says, and he tosses the pillow aside. "Useless goddamn—you okay?"

 

            "Hi." Cas gestures with the bag of toiletries, hesitant. "Can you—?"

 

            "Yeah. Come on." Dean scoots inelegantly along the mattress and pats the spot next to him.

 

            Cas sits clumsily, the mattress giving beneath his weight so that he is tilted precariously over into Dean and then away again. Dean takes Cas' bag to start fishing through while Cas turns his back, hooks a thumb into the back of his collar, and pulls his shirt off over his head. He half-folds the bundle of flannel, of sweater, and leaves his hands tangled in it as he waits for Dean. There is a draught that whispers in under the front door, chill and sweet with the woods-wet smell of pine and damp soil, and it lifts goosebumps along Cas' spine. The touch of Dean's hand, when it comes, is warm and rough, the pads of his fingers calloused beneath the lukewarm cream.

 

            Cas closes his eyes.

 

            He can't quite put his finger on when this became a routine of theirs, but he is grateful for it. By the end of each day, there is a dull throb of discomfort tucked at the base of Cas' shoulder-blades, the muscles curling tight and tense, something that hunched him over and over until he was so curled into himself that Sam began to worry he should see a doctor; he was the one to first suggest the IcyHot. Dean rubs it into Cas' skin now, slow and reassuring, and the faint, cold prickling of it spreads to bleed through Cas' tension. It starts to burn warm, seeping beneath his skin and settling. Cas exhales. It's been too long since he stretched his—

 

            "That helping?"

 

            Cas opens his eyes. "Yes," he lies. He can still feel the phantom itch of them, even months after he fell. Rationally, he knows that his real body is immense beyond human comprehension, lightning and light and lionsong, but in this skin, he feels the loss like something has been carved from him. "Yes, thank you."

 

            Dean hums to himself, satisfied.

 

            As Cas lets Dean work, he becomes conscious of Sam emerging from the bathroom. Sam looks at them, then away again; he never makes a point of avoiding looking at Dean's hands on Cas' skin, but he doesn't comment. He gives them space. Dean's hands are practiced in stabbing and slashing, in taking apart firearms and scrawling devils' traps, and here, on Cas' skin, they are gentle. It lasts, on average, two to three minutes—the longest that Dean ever touches him. Cas doesn't care what Sam thinks; he'll take what he can get.

 

            "Thank you," Cas says, at last, when Dean's hands drop away from him.

 

            "Don't sweat it." Dean wipes his hands on the thighs of his jeans, and he offers Cas a smile. "You good?"

 

            Cas nods.

 

            "You got your music?"

 

            "Yeah."

 

            "Okay." For a moment, Dean pauses, sitting there close enough beside him in a thin T-shirt that Cas can feel the muted warmth of him through his clothes, and his eyes move slow, distracted, over Cas' face. His fingers twist idly in the seam of his jeans. "Yeah. Cool."

 

            Cas takes a deep breath and hauls himself awkwardly up away from the air-mattress, and he returns to his couch, his shirts tangled in one hand. He strips down to his boxers, shrugs into a plain T-shirt, and kicks his clothes into a corner to keep out of the way. He climbs under the blankets.

 

            Dean is the last one to turn in, after Sam has set up their gently-crackling radios and phones on the center table, and then Cas is left in the darkness and the quiet. His phone is cold against his thigh, under the blankets, but he leaves it alone. He tries it Sam's way.

 

            He keeps himself in silence and he suffocates in it. The heaviness, the stillness, weighs like an anvil in his chest, and he can feel himself straining for sound—picking up Dean's breathing, Sam's snores, the dull clank of water through pipes—anything to fill his echoing skull. The aching, unbreakable quiet tightens around him until he can hear his pulse drumming in his ears, and the distant rumble of Sam's snore is a light-year away.

 

            He breathes, and he uncoils his headphones from his phone. Track 13: Blizzard, Montana. From the beginning.

 

 

* * *

 

 

_Father, forgive me. Please, Father, let them know no suffering._

_Desperate, knees muddy, beneath the star-torn sky. A useless, empty prayer, stoppering his throat like a bottle at sea._

_Please let them know no pain, Father. Please—let them die._

Cas opens his eyes.

 

He watches the faint hum of blue light across the rafters while he thumbs the volume on his phone down, bit by bit, until it's off, and shadows lift and move in the corners of his eyes. It’s an old dream, well-worn—he doesn’t think about it. 

A little before six, bodies in the room begin to move. At five after six he's standing near the door of the bathroom, listening to the hiss of hot water inside where Dean is showering, waiting for his turn. He feels stiff and his feet are cold.

            When Dean comes out, in a wave of humidity and steam, Cas slips in behind him and shuts the bathroom door, locks it. The mirror is fogged, the wood floor wet in flat, footprint-shaped puddles. It smells heavily of the soap Dean uses—a smell Cas likes. He sits down on the edge of the bathtub for a minute, adjusting to the new morning noise, breathing that warm, comforting smell.

            Sam's limited them to ten minutes shower-time, tops. They want to be on their way up the paths to the cave system at half-past, if not earlier. There are towels heaped on the floor; he's the last to shower. Ten past.

            He gets up, pulls his shirt off, pulls his boxers off. The sole mirror is about the size of his head and bolted high up above the sink. Without going up on his tiptoes, he can only see his face.

            He reaches back, gently palms the space beneath his shoulder-blades. His back feels better than it had yesterday. There's still the faintest heat in his skin, numbing the pain.

            He lets his hand drift down, past the small of his back, across the outside of his thigh. Lets it drop, then. Looks hard at himself in the mirror. The humidity is clearing away, the fog melting from its surface. In it he looks tired, sore. Not himself.

            There are a few carefully-closed prescription bottles in the toiletry bag that Sam and Dean share, wilting open on the shelf above the toilet. Sam's. He's not himself, either. The Trials left him in a bad way—he's only just now getting the weight back that he lost—he has to medicate to sleep, for now, at least. His stamina isn't what it used to be. But every morning his jogs get longer and he comes back less breathless, and usually Cas is waiting for him with coffee while Dean, somewhere in the room, or in the back parts of the bunker, drags himself out of bed. It's sort of their ritual, though neither of them planned it. Coffee in silence while Sam gets his breath back, and Cas observes him tenuously from beneath his eyelids, trying to think— _if he can recover—so can I._

            Cas reaches in and picks a bottle up—the name is long and he isn't sure what it's for. The pills inside are white and unassuming. He puts it back.

            There's no medicine out there for him, but at least there is for Sam.

            There's a rapping on the door, and Sam's voice. “You okay in there? You fall in?”

            “Sorry.” Cas leans over to turn on the water, and Sam's footsteps fall away.

            He showers perfunctorily, brushes his teeth and avoids his face in the mirror. Pulls on one of Dean's old Henleys and a hemmed-up pair of Sam's jeans, a new pair of rubberized boots, two button-ups. There's still no word from the Harrisons, and it's been hours since they should have checked in. The caves were supposed to be a brief, cursory check, sweeping for anything suspicious, before they doubled back to meet up with the Winchesters to discuss their next step. It's autumn, and Sam says the caves will be cold. Dark. Wet.

            In the main room Sam and Dean are killing time as they wait, draw-string backpacks stood at their feet; there are three pistols between them, all loaded with silver bullets. They're wearing helmets, and an empty white one rests on the bed, waiting for him. Cas looks to them, murmuring quietly to each other with their shoulders turned in. Sam is probably trying to reassure him of something—Cas can tell by the way his face is pulled down, the tilt of his head.

            Cas swallows as he joins them, rests the heel of his hand on the butt of his borrowed pistol for lack of anything better to do. It's almost half-past six by the cuckoo clock on the wall, and very suddenly he wants to be out in the air, on his way to something, anything, even if it is a hole in the ground full of werewolves and human bones.

            Then Dean is turning to him, asking how he slept, and Cas jolts, though Dean doesn't seem to notice.

            “Fine,” he says, “I guess.” He doesn’t tell Dean about the dream.

            Dean's eyes search him from underneath his helmet—a red one with a head-torch, left behind by the Harrisons—and Cas can't keep his gaze; he looks sideways, down at the edge of a rug on the floor.

            “Okay,” Dean says quietly, and reaches down to squeeze Cas' wrist for an instant; then he pulls away, back to Sam.

 

The Harrisons left them with only the basics—rope and carabiners, helmets and flashlights and flares, and the general gist of how to rappel, if they need it. They shouldn't—they were clear on that. But just in case, just in case.

 

            Their silence on the radio has become deafening. Cas feels a twist of worry in his gut. In all reality, they're probably fine—lost at most. But he can't help but wonder. Fear the worst.

            They make a noisy shuffle towards the front door, toward the burgeoning daylight and shrill mountain birdsong, and for a moment Cas feels tremendous guilt, seeing Dean's shoulders slumped beneath the weight of the rope he's carrying. Sam is sick and Cas is—whatever he is—and it's all, as usual, on Dean, now, the responsibility of carrying them until they can carry themselves again. And they will—Cas knows that. Sam will get better, and he'll get better, and Dean can step back, and they'll all take care of one another instead. It's kind of a far-off dream. But it's one he dreams.

            And maybe this will be good. Fresh air and exercise, camaraderie, a black-and-white enemy with a sure-fire weakness.

            Nothing to be afraid of. Everything to hope for. Later, Dean's hands on his back, smoothing his pain away.

            Cas follows them out into the light.

 

* * *

 

            It's a twenty-five minute drive from the motel to the road which curves nearest the cave system as marked on Sam's map, on a road which narrows to a single lane, then fades to a dirt track. The Impala judders over rocks and potholes and places where rain has carved away the dirt road until they bounce in their seat with the car's suspension and Cas can feel his teeth click together. The trees press in close either side of them, thin and peeling in long pale strips; rainwater glints in puddles, flat and still, catching the thin colours of dawn where it bleeds through the pines.

 

            As Dean drives, Sam pulls his phone out of the pocket of his jacket. He fiddles with it for a second, muttering under his breath.

 

            Dean glances over. "What's up?"

 

            "No signal." Sam works at it for a moment longer before he gives up, pushing it back into his pocket. "They're definitely not gonna be able to check in now."

 

            The radio becomes fragmented with static as they drive deeper in the mountains, turning over and over, near-frantically, as it searches for a station it can easily reach - snatches of classical, _traffic backed up all the way through I-64 so if you're looking to get to Charleston before noon,_ the tinny strains of a pop melody, white noise, _unidentified with signs of what experts are referring to as some kind of wide-scale thermal acci—_ and then Dean switches the radio off. They rumble and rattle in silence up the last of the road until, through the trees, there is the battered shape of the Harrisons' pick-up.

 

            "Damnit," Dean says, and he pulls over, eases the Impala under the shelter of the pines. He kills the engine and climbs out.

 

            The pick-up has settled squarely into the mud, its tires caked, and there is no sign of Sue, Pete, or Kurt. Cas gets out of the Impala to follow Sam and Dean over to check it.

 

            Dean curls two hands around his eyes to peer through the truck's window, and Cas sweeps a hand over the hood. The touch of the metal is cold, wet with dew. "They didn't come back last night," he says.

 

            Sam pulls out his phone, glances at the screen before he tucks it away again with a sigh, and says, "Still no signal."

 

            "Shit." Dean pushes himself away off the truck and dusts his hands off. "Okay. Where's this cave, then?"

 

            They retrieve the spare caving equipment from the trunk of the Impala— _better safe than sorry,_ Sam says, as he stows a few things into the front pocket of his backpack. He hands Dean and Cas climbing axes, and takes one for himself. Cas turns it over in his hand, feeling its heft and weight.

 

            And then they hike. It's another three miles from the road to the mouth of the main cave, up craggy slopes, winding through the trees, with Sam at the fore-front, map in hand. Dean, of course, complains most of the way up.

 

            “No one's been in these caves yet, is what you're saying,” he says, breathless, when they stop to drink some water. Cas lingers at his side, looking down over spilling terraces of moss and rock; he can hear a river in the far distance.

 

            Sam shakes his head. “They're newer. Entrance only opened up a couple of years ago.” He's peering at his map, holding his compass in the flat of his hand. “But Pete said he thinks they're connected to some other caves in the area—like a big maze.” He points south, and Cas follows his finger, though there's nothing to see but trees that way. “I guess people have been in and out of those, but not enough that they've been named.”

 

            “Great,” Dean mutters. “Virgin territory.”

 

            Sam doesn't acknowledge him. He starts up the trail again, picking it out from among scrag and fallen leaves, and Dean and Cas follow after.

 

            The sun starts to climb into the sky as they go, and eventually Dean's complaining drops off in favour of keeping up his breathing. Cas, for his part, is keeping pace. There's an ache in his legs that he likes. The air is cold and good in his mouth, his lungs.

 

            Halfway, something seems to change—the trees hang lower, darker; the sunrise gloom makes the air grey, everything around them greener and sharper. The sound of their boots in the scrub and the dirt is louder. No birds singing. Barely even a cricket-call.

 

            Cas thinks about the Harrisons. Sam's radio is still whispering faintly at his hip, static with no voices in it.

 

            There are a lot of ways to die in a cave. Even a cave with no werewolves in it. He swallows, takes a few jogging steps to catch up with Dean, walk beside him instead of at his back, and Dean glances at him from beneath the rim of his helmet.

 

            “You good?”

 

            “Got a bad feeling,” Cas says. He sees Sam's head twitch backward, in their direction. He's smart enough not to play into unease, but he's got to be feeling it, too.

 

            “Yeah,” Dean says. “Happy thoughts, though.” He smiles, looks forward to where the trail takes a steep incline to the right.

 

            Sam stops midway up, and then goes to his tiptoes, pointing up through a parting in the rock.

 

            “That's it,” he says, and knees his way up the rock face—it's only about three feet, but Cas feels a little glimmer of pride. A month ago Sam wouldn't have been able to do that. He’s stronger now. Not quite his old self, but close.

 

            They follow him, toeing up through crevices in the rock, and when Cas has finally hauled himself over the lip of the face, he sees that the ground has levelled forward, like a shelf on the edge of the mountain—

 

            And there, like a gaping mouth, a total drop into black, the entrance of the cave.

           

            Cas stares down into the dark.

 

            He is familiar with fear, as an abstract and, more recently, in practice, but he has never felt it like this—like he can’t quite breathe.

 

            Sam and Dean don't seem as bothered—they're laying out rope, leaning over the edge, handing things back and forth. Cas stands behind them, his throat tight—the idea of stepping any closer fills him with dread. They're going to rappel down the side, though it's small, and he—

 

            All he can think is, _I won’t fit._ His wings, the bulk of him, all his vastness and power and glory – he won’t fit. A creature of light has no place underground.

 

            “—? Earth to Cas?”

 

            Cas lifts his head. “I’m listening,” he says.

 

            Sam half-smiles. “Wrong answer, dude. I said, you ready to go?"

 

            Cas steps across to the edge. When he stands at the lip of the cavern, he can see that it isn't deep. It's perhaps ten or twenty feet down, shallow enough that sunlight glints in puddles of stagnant water. From there, it slopes away deeper into the gloom, but slowly - the territory of a careful walk, rather than any real caving. Nothing to be afraid of.

 

            He rolls his shoulders back, testing out the dull ache at the base of his shoulder-blades.

 

            Abruptly, there is Dean at his side. He reaches out a hand, skims it the length of Cas' arms to brush cold fingertips over the inside of Cas' wrist, to sweep across the back of his hand. "Easy, Cas," he says. "Come on."

 

            Sam shows Dean how to affix the line, and before Cas knows it, Sam is gone, down, paving the way into the dark; Cas can hear his boots hitting the cave walls. He's on the floor in a moment, and Dean lifts an eyebrow, gestures _after you;_ Cas, as ever, follows.

 

            Dean's weight on the end of the line is a godsend, he thinks, clipping his carabiner onto the rope, sitting down gingerly on the edge of the cliff. Inside, close enough to kick, if he was feeling funny, is Sam, hands on his hips, smiling reassuringly up at him.

 

            “Come on,” he says. “You can even slide down on your ass if you want. It's not steep.”

 

            Dean snorts behind him, and Cas feels himself lighten a little. They're not afraid. It's a hole in the ground. They've all seen Hell, and more besides.

 

            Cas pivots, grips the line. He slides more than rappels, the rope singing through his gloved hands, and before he really knows it, Sam's hands are on his back, easing him onto his feet among the broken rocks and coiled line.

 

            He looks up, at the mouth of the cave some ten feet high, Dean a shadow at its top, a narrowing slate of light, and he swallows.

 

            Naturally, Dean curses and complains all the way down, until he plants his feet solidly on rock and lets out all the air from his lungs.

 

            For a moment they stand there, to let him catch his breath, and Cas looks past Sam to the narrow tunnel that is the only exit from this chamber. He inhales, reaches up to turn on his head-torch. He's relieved to see that it penetrates the darkness—illuminates quiet stone and scattered rock, ridges in the cave walls formed by water over centuries, or some great tectonic catastrophe. He sees, now, a thin stripe of water flowing from the entrance at his back, deep into the tunnel, wending and winding its way among the pebbles.

 

            Cas glances down. Between his boots there are a few strands of grass, clinging to life in what little sunlight bends its way beneath the lip of the cave. Something about it makes him breathe a little easier.

 

            Dean reaches across, raps his knuckles on the top of Cas' helmet. "Come on," he says.

 

            The brothers flip their flashlights on and begin to carefully make their way down. Once past the dry threshold of the tunnel, the rock is slippery underfoot at first, worn smooth by the slow trickle of rainwater; as they pick their way deeper it breaks up evenly, sharp and jagged at the edges. Cas places his feet carefully.

 

            “They would've come in this way,” Sam says, in a strange, cold whisper that hisses and bounces off the walls of the cavern. He can barely stand up straight; his helmet scrapes the ceiling every now and then; Cas crouches a bit as he goes, but his head clears the rock with ease. “Keep an eye out.”

 

            “For?” Dean asks. Cas pauses to look back at him, sees his flashlight pass over a black hole in the wall, too small to enter, but gaping there, like a mouth. He contains a shudder.

 

            “Bones. Footprints.” Sam sweeps his light over the mud and rock at his feet. “Rope.”

 

            The pale watery beams of their flashlights wash coldly over the cave walls, picking out where the ceiling dips, where the tunnels veer away.

 

            Cas focuses on his feet so as not to think about the crushing darkness that he can feel pressing in on him, the way the cave narrows and narrows until they walk single-file and Sam leads the way with one hand skimming over the wall at his side.

 

            At one section, Sam tilts his shoulders to fit through, and Dean follows, sucking in his breath theatrically before glancing back at Cas with a grin. Cas sets his jaw and moves through at an unsteady shuffle. The walls graze his arms on either side, even when he angles his shoulders, and the wet creep of water down over the rock soaks through his shirt.

 

            Mercifully, the cave opens up some five or six feet later, and Cas breathes. He rolls his shoulders back until they pop.

           

            For a moment they pause in the open chamber so that Sam can fumble with his pocket map and the notes on a napkin that Pete Harrison had scribbled out before they left—approximations of the cave, arrows toward the exit he thinks exists. By all appearances the system should be a fairly simple one—like a traffic tunnel bored into the mountain, a huge S-curve that deposits down-mountain, fed with tributary corridors too small to explore. Impossible to get lost in. Child's play.

 

            Cas stands near the entrance to the chamber, arms crossed, watching, while Dean illuminates Sam's papers with his flashlight and they murmur to themselves.

 

            It's quiet down here, except for their own noise—the sound of their boots on the floor, every breath or word they say an echo, but all of it contained.

 

            He's uncomfortable. There's nothing down here as far as they can see yet. No werewolves and no Harrisons besides. No bones or rope or abandoned equipment. The chamber they're standing in is only eight feet wide, maybe, ten feet across. At its far end the tunnel continues, barely wide enough to accommodate a human body.

 

            And the silence. It fills every inch of this place.

 

            They walk on, into the narrowing tunnel, down and down. When the walls finally diverge, some fifteen minutes later, Sam disturbs a stone as he walks and it goes skittering, unseen, beyond the edge of the darkness, and the sound of it clicking and cracking against the rock lasts an age.

 

            "Hey, heads-up," Dean says, suddenly. The sound of his voice makes Cas jump.

 

            Dean lowers the beam of his flashlight to pan over the floor. It takes Cas' eyes a moment to focus on what he is being shown: splinters of bone, scattered and broken, some still stained dark with traces of old meat.

 

            "Breakfast, anyone?"

 

            Sam backs up instinctively, sweeping his own flashlight down to glint harsh and white off the wet floor and pick out the remains. It's something of a disorganised exhibit—at a glance, Cas can identify fragments of rabbit and deer, fox and cat, and the tattered shape of a single bird's wing. He feels a sharp, icy prickle down his spine.

 

            "It doesn't look like any human remains," Sam says, frowning down at the mismatched collection. "Just animals and—what is that?"

 

            He drops into a crouch and stretches out a hand to carefully sweep his fingertip through a small, colourless puddle of something thick and congealed. Then he jerks his hand back.

 

            "Okay, no. That's skin."

 

            “Skin?” Cas echoes.

 

            Dean makes a retching noise.

 

            Sam wipes his hand on his jeans, his nose wrinkling.

 

            “Yeah. Looks like when a shifter sheds.”

 

            Dean scoffs, leaning back on his heels. “'Cept shifters don't kill the way these things kill.”

 

            “So they were wrong,” Cas says. “The Harrisons.”

 

            “Maybe. Maybe not.” Sam stands up again, head bowed forward under the ceiling. “I mean, it _looks_ like skin—” He pauses, reaches up to fiddle with his head-torch. Sighs. “But I dunno. It's dark in here. Could be anything.”

 

            Cas watches his hand come down to rest on the climbing axe slung into his belt. Sam's shoulder tightens. He swallows.

 

            “Well,” Dean says, “at least we brought silver.”

 

* * *

 

 

            The tunnel remains wide after that. They can walk upright, at a comfortable distance, and Cas reminds himself to breathe normally, though the constant smell of damp stone is a queasy one.

 

            He and Dean keep their lights trained on the floor, sweeping side to side like searchers in the woods. Here and there, bone fragments litter the ground, flashes of white in the never-ending dark, but nothing of interest.

 

            Just ahead of Cas, Dean stumbles, his ankle turning over in an unseen crevice. He swears, and Cas grabs his elbow to steady him. Dean straightens up breathlessly, shaking his foot out. "Thanks."

 

            Cas gives him a small smile.

 

            “Woah,” Sam says, suddenly, stopping abruptly. “On your right.”

 

            He angles his flashlight down and out a ways, and Cas feels his heartbeat pitch up, just a little.

 

            Past a crop of low boulders the floor drops off into absolutely nothing, a stalactite-studded hole that eats up Sam's light like a monster in itself. It's nowhere near their route, but Cas feels dizzy suddenly, sharp pinches of adrenaline in his spine, just knowing that it's there.

 

            “Damn,” Dean says, letting out a low whistle. He picks his way carefully over to the boulders, and Sam follows; Cas stays, staring at it.

 

            “Don't,” he says, through a lump in his throat, too softly to be heard, but the brothers are already there, kneeling carefully on the boulders to shine their lights down into the crevasse.

 

            “That's a long fuckin' drop,” Dean says, with a wry morbidity. He twists, a shadow-shape against his own light, and Cas sees the vague motion of his arm. “Come look at this, Cas.”

 

            Reluctantly, Cas follows the points of light at their heads, his elbows in close to his body.

 

            Dean reaches out as he approaches, takes his elbow tightly in his hand. He's leaning on the rock too casually, and Cas can't help but picture, in horrible flashes, stone crumbling, their three bodies toppling forward—

 

            “Gotcha,” Dean murmurs, flashing him a reassuring grin that's too bright in the torchlight.

 

            Cas leans over only centimeters, but it's enough to see.

 

            In his peripheral vision, Sam picks up a small, jagged rock and drops it over the edge.

 

            He stares after it, though it's lost to their light completely. The glow from his helmet vanishes against the blackness.

 

            It doesn't take long for the rock to hit the bottom, but it takes long enough.

 

            Cas glances at Sam. He can see his eyes shifting in the light, the way they do when he's thinking hard.

 

            “Yikes,” Sam breathes. “That's maybe—fifty feet deep?”

 

            “Hope they didn't fall down there,” Dean says softly. No one has to ask who he means.

 

            For a moment they stand there, looking into it, silent.

 

            Cas thinks—he can almost feel the weight of all the air that's settled inside it, this hole. What he's breathing in feels stale and old. He shifts his center of gravity, very slowly; without his noticing, he realises his hand has come down, gripping Dean's forearm, and Dean doesn't seem to have noticed, either. His own hand is still secure on Cas' elbow.

 

            And then—

 

            “Wait,” he says, and is nearly blinded by the converging beams of Sam and Dean's headlamps turning into his face. He shuts his eyes, parts his legs a little for balance. “I thought—”

 

            He doesn't need to tell them to be quiet. They seem to have gathered that on their own, and he can still feel their lights on him, turning his eyelids shades of orange and red.

 

            He thought he heard something—but he doesn't say it yet; how to say something like that? They're alone down here, half a mile underground, above a pit three stories deep—but he thought—

 

            It wasn't much. A murmur, a sliver of a voice. It could have been a carabiner hitting rock, or their clothes shifting, or any number of things—

 

            “What is it?” Dean whispers, sounding wary.

 

            Cas opens his eyes, looks at him as best he can, beneath the torch over his face. Swallows. “I thought I heard someone,” he says.

 

            To his surprise, Sam immediately tenses next to him, rising up onto his knees, gripping the boulder in front of him for balance as he peers further into the hole. “Are you sure?” he says, a little too loudly. His axe batters against the rock and Cas instinctively reaches out to snag the lip of Sam's jacket collar, feels Dean's grip tighten on his arm. “Maybe—”

 

            Dean seems to catch his drift, and he shouts down into the empty space. “Hey!” he calls, and Cas startles, crouches down swiftly next to him, afraid of tipping forward. “Anyone down there?”

 

            “Sue!” Sam calls. “Kurt!”

 

            “Pete!”

 

            “Stop it!” Cas says, abruptly, wildly, and the brothers go quiet, startled.

 

            They look at him, blinding again, confused.

 

            “Stop it,” Cas says again, softer. His heart is throbbing in his chest. He's gripping Dean's arm so hard he can feel bone underneath his fingers. He swallows thickly past the lump in his throat. “We still don't know what's down here.”

 

            Sam sets his jaw. He nods, almost imperceptibly, a flicker of motion in all the shadow.

 

            “We should check if we can,” Dean says after a moment. Cas can feel him looking at him, feel his other hand searching blindly through the dark for Castiel's, taking it almost absently. “There's gotta be a slope or something. Look for rope, or broken equipment. Just to be sure.”

 

            “If they fell all that way they didn't make it,” Sam says softly.

 

            “We should at least try.”

 

            They're talking past Cas now, in the void between him and the edge.

 

            Cas lifts his head, points his head-torch at the high, vaulted, dripping ceiling, inhales slow through his nose.

 

            They don't know what's down here. But he'd felt—something else, some other instinct, a sharp, hot fear when they started shouting—

 

            A sense, not that there was nothing down there to hear them, but that there _was_. He feels it like the flicker of a shadow in his periphery, feels it in his borrowed, hollowed marrow.

 

`           Dean starts to pick his way carefully around the edge of the hole, his head ducked so that the lamp on his helmet can illuminate the ground and leave his hands free. As he passes, Cas snags him by the elbow, holds him still. Dean looks back, surprised; under the searing glare of his head-lamp, his face is washed out into undeterminable shadow.

 

            "Hey," Dean says, and he reaches up with his hand not held still by Cas' clutching fingers and tilts the beam of his lamp away. Cas can pick out, now, the curve of his mouth, the line of his jaw, and against all odds it does calm the nervously humming centre of him. "Cas. What's up?"

 

            The words catch in Cas' throat. He runs his fingers down Dean’s arm, tracing the seam of his jacket sleeve, brushing his fingertips over Dean’s wrist. “Be careful,” he says, at last. “Be safe.”

 

            Dean’s mouth tilts up at one side into a sweet, lopsided smile. “Always am.” He winks. He reaches out, bumps his knuckle at the underside of Cas' jaw. “Never got killed yet, have I?”

 

            “Never stayed dead, at least,” Cas says reproachfully, and Dean laughs.

 

            Dean turns away, then, and moves deeper into the darkness until eventually he is lost to it, nothing visible but the indistinct shape of him, sliver-thin in silhouette and reduced to a single illuminated point as his head-lamp moves and ducks and shifts. Sam touches a reassuring hand to Cas' shoulder as he passes, offering the flash of a warm smile from under the head-lamp. Cas is left alone, staring at the pit in the earth. The beam of his lamp extends so far as to dimly pick out the crags at the hole's edge, and then it is black.

 

            Unwillingly, Cas steps closer. The hole is not evenly circular, but rather like a jagged wound, something torn in impatience, and the edges slope slightly inwards, worn smooth by water and time. There are cracks in the rock, narrow crevices, jutting points. Cas follows it, stepping uncertainly, his throat tight with the moment as it plays out in his head—the moment he loses his footing and slips and scrambles desperately for something to hang onto and falls.

 

            He traces the route in front of him with his flashlight, careful and steady as he moves, but his mind is occupied, and so he doesn't see it until he nearly trips over it. A rappelling anchor, stabbed firmly into a narrow crevice in the earth, from which thick rope strains, over the rocks and over the edge and down into the dark. The anchor is shiny, new; in the harsh light of Cas' lamp, when he drops into a crouch for a better look, he can still pick out the smears of fingerprints.

 

            "Over here," Cas calls. His voice splinters off the walls of the cave, bounces back and loses shape. "I found something."

 

            He moves aside, stands clear so that there is room for Sam and Dean as they press in for a look.

 

            Sam says, "Shit."

 

            Dean rubs a hand over the back of his neck. "Don't tell me. We gotta—"

 

            "We have to check it out." Sam lifts his head to look up at Dean. "You got a flare handy?"

 

            "Yeah, somewhere." Dean shrugs one arm out of his backpack and half-lifts a knee to support the base of it as he digs through the front packet. He sways, unbalanced; Cas reaches out a hand to steady him. At last, Dean comes up triumphant. "Here we go."

 

            Sam helps him pull taut the drawstring of his backpack and heave the bag back on, while Dean works on the flare. He twists off the cap, shimmies cautiously over the rock to get away from Sam and Cas, and holds it out away from his body before he scrapes the end against the cap. It ignites in a sizzling burst of hot sparks that throw irregular, incandescent shadows over the walls, over their faces, picking out every crevice and dark place, and they jerk back out of instinct away from the fizzing fountain of light. It washes Dean out, bleaches him of colour. It picks out the bruise-like bags still beneath Sam's eyes after all his bed-rest and recovery. The light moves in a slow, uneasy waves, the hot pinkness rippling.

 

            Then Dean holds it out at arms' length to fizz and splutter over the gaping maw of the cave, declares a solemn, "Sayonara," and lets it go.

 

            The flare falls. Its light is swallowed by the darkness, only casting its shimmering, hazy glow over the walls around them. The three of them crane tentatively over the edge of the hole to watch it pick out the unevenly sculpted walls, the widening throat of it, until it no longer sketches out the edges for them but is engulfed by the space around it. It exposes a cavern larger than they had expected, and it falls, and its fizzing and spluttering light dwindles to an unsteady pinprick, and it falls, and Dean says, "Jesus," and then it hits the ground with a dull _thunk_.

 

            "What's that?" Sam asks, and he points.

 

            Cas follows his gaze and finds that at the bottom of the pit there is— _something._ It is indistinct, shapeless, but it stands out from the rest of the dark rock and puddling water.

 

            "No way that's a body," Dean says, but he sounds unsure.

 

            The sigh that Sam lets out through his teeth is decidedly reluctant. "Only one way to be sure."

 

            "Hey, after you, Indy."

 

            Sam makes no immediate move. He looks back at the anchor, and then at the drop, and at whatever is waiting for them at the bottom. Then he holds out two hands - fist flat on palm. Dean makes a noise of complaint in the back of his throat, but matches up, and one, two, three—Sam throws rock. Dean throws scissors. Cas watches their hands cast abstract, shapeless shadows across the rock in the light from their head-lamps.

 

            "Goddamnit," Dean mutters, and he flattens a hand over his helmet to adjust it. "Fine. Fuck."

 

            Cas stands back, quiet and anxious, as Sam works the rope, hauls it up hand over hand, and fixes Dean in. Sam checks Dean's hold, and he double-checks, and he worries at the strap around Dean's waist until Dean swats his hand away.

 

            "Goddamnit," Dean says again, as he fastens his backpack to his carabiner, letting it hang, bulky and awkward, between his legs. "Okay. I'll, uh. See you at the bottom, I guess."

 

            He looks at Cas, and Cas doesn't know what he sees there, but his expression changes, and the flash of his smile is a little thin and forced, but appreciated nonetheless. Then he steps carefully back over the edge and down.

 

            He calls up when he reaches the cavern floor, his voice small and echoing. "I'm good," he says. "Rope clear." He's maybe thirty feet down or so, little more than a shadow in the dimming pink light of the flare.

 

            "Is it a body?" Sam calls back.

 

            "Nah. More of this weird—skin, or whatever. But there's footprints here, and another tunnel. Plus a Snickers wrapper. Since apparently the Harrisons hate the environment."

 

            "You think it's definitely them?"

 

            "Footprints aren't more than a couple days old. It's gotta be."

 

            "Alright. We're coming down," Sam calls back, and then he pulls the rope back up, and he turns to Cas. "You ready?"

 

            Cas nods. "I'm ready." He is secure in Sam's competent hands; he trusts Sam not to let him fall. It does nothing to calm the way that his heart stutters fast at the sight of the drop, the way he can feel his throat constrict as he looks at the mouth of the cavern. Sam puts the last touches to Cas' harness, checks he's all safely fastened in, and then Cas sits on the edge, feet dangling. Below, there is Dean, too far down for Cas to see his face, but he imagines he is smiling. Cas' fingers grip the edge tight.

 

            "Come on," Dean calls up, and he holds his arms out. "Promise I'll catch you."

 

            Cas shimmies carefully off the edge, planting his boots solidly against the rock, and then he is hanging.   He climbs down, slow and deliberate, his fingers vice-tight on the rope, letting it out inch by inch. Last time, he let the rope out fast; if he does that here, he'll break both his legs.

 

            He is distantly aware that he is taking a long time, painfully slow, but he tunes it all out to focus on the unsteady rhythm of left foot, right foot, left foot, right foot. The rock is slippery and uneven underfoot; the fizzing light of the flare below glints off his carabiner, washes everything faintly pink, but for where his head-lamp glares harshly white.

 

            "Halfway there, Cas," Sam calls from above. "You're doing great."

 

            Cas breathes through his teeth. Halfway there.

 

            Then, at the base of the cavern, the flare splutters, flickers, and goes out, and Cas is in darkness.

 

            He freezes. His hands clench around the rope, every muscle in his body locking, but being left with the sharp white beam of his head-lamp makes his head spin, and one of his boots slides out. His other foot loses purchase as he slides, and then Cas falls.

 

            It's only an inch or so of slack, but it's enough that it jerks his harness, gives him a split-second of terrifying, gut-wrenching weightlessness before the rope pulls taut and Sam shouts above him and then his knee hits the rock wall hard. Pain spirals white-hot from the point of impact, and he gasps out, disoriented, and then he is swinging away from the rock. He is untethered from everything, his legs hanging, the blackness tightening around him like a fist. He is lost in the dark, lost and insignificant some miles underground in a tiny, fragile human body, and he clings to the rope in desperation for anything to keep him pinned to earth. He can't breathe.

 

            "Cas," Dean is yelling. "Cas? Cas, you okay?"

 

            Cas can't answer; the dark has a hand around his jaw and it squeezes, and he can't breathe, and the moment of his complete icy detachment from the rest of the world lasts and lasts until finally he hits the wall again.

 

It jolts the breath out of him, abrupt and painful as his shoulder collides hard with solid rock, but he fumbles desperately with his feet to turn himself around, to stay on the wall. He can feel the smallness of the cavern, the narrow crushing clutch of it, and he is trying to plant his boots solidly on the slippery rock in the dark, trying to breathe as panic spikes in his gut and makes his hands shake. The scraping of his boots seems to ring out in the echoing quiet, and Sam and Dean's voices only make the silence underground seems more expansive and restless.

 

            "Fuck—Cas? Talk to me." The beam of Dean's head-lamp below him is dancing, agitated. "One second, I'm gonna get another—hold on, Cas."

 

            The Castiel of old is accustomed to the passage of eons, standing guard over the rise and fall of civilisations like ant-heaps; now, he waits for Dean to light another flare, and it seems to take forever. Finally, there is the rough sound of Dean striking the cap and end together, and then, again, the cavern bursts into light.

 

            It takes a moment for Cas' eyes to adjust; for a second, the fidgeting pink glow of the glare sends flickering shadows across the walls, shapes like something moving in the dark just beyond Cas' periphery; for a second, the sound of his boots as he adjusts his position is a whisper like something speaking out of sight.

 

            "Cas?" Dean calls. "You okay?"

 

            "You're nearly at the bottom," Sam says from somewhere above Cas' head. "You can let the rope out a little faster and you'll be there in no time. I've got you."

 

            Cas takes a deep breath, and he descends.

 

            At last, his feet hit solid ground, and his knee buckles. He stumbles backwards, and then Dean is there, his hand on Cas' elbow, Cas' shoulder bumping into Dean's chest, and Dean holds him still.

 

            "Hey," he says. "There you go. Alright?"

 

            Cas looks across at Dean, the hotly sparking, shimmering light of the flare picking out the worried crease of Dean's brow. He lifts an unsteady hand to check his helmet, straightening it on top of his head. "I'm fine," he says.

 

            Dean’s hand runs down the length of his arm, his fingers curling gentle around his wrist. He tilts his head to peer into Cas’ face, uncertain, but he worries at his bottom lip with his teeth and his other hand hovers uncertainly in the air between them.

 

Cas takes a deep breath, rubs a hand down over his face. There is sweat collecting under the headband of his helmet; it trickles down from his hairline into his ear. “I’m fine,” he says again, and his voice is steadier now. He meets Dean’s eyes, and he can’t quite smile with his knees still shaky beneath him and the memory of the weightless dark tangled in his throat, but he nods. His fingers find Dean, brush gently over the backs of his knuckles. “Really.”

 

            Dean raises his head to look up towards Sam. "I got him. Rope clear," Dean shouts, and Cas flinches away from him slightly, unable to shake the sense that they are being far too loud in a space that is not theirs.

 

Cas doesn’t say anything, already of the sense that Sam and Dean think he is being jumpy, paranoid—he doesn’t want to give them any further reason to think that he can’t handle himself down here. He steps past Dean, towards the sludge of molten skin. It oozes over the rocks and puddles in a small hollow, thick and glutinous, with a sick, oily gleam in the low light.

 

Hesitantly, Cas nudges at it with the toe of his boot. It’s solid enough that it yields, leaving a kind of dent in its surface; it takes a second to drip and spill over the rock and even itself out. It’s not recent.

 

            Behind him, Sam makes quick work of the way down, his footsteps on the cave wall sure and confident. As he nears the base of the cavern, Cas hears it—the faint, distant shush of voices whispering.

 

            He lifts his head, turns to follow the sound, and finds himself staring at the entrance to another tunnel. Maybe he's mistaken, he thinks, and then he hears it again.

 

            One voice, and a response. An echo of an echo, so faint that Cas can't pick out any details, but definitely something.

 

            “—okay? Cas?”

 

            Distantly, Cas realises that he is being spoken to. He straightens and turns around. "What is it?"

 

            "You tell me," Sam says. "You were staring off into space like you—"

 

            "I heard something," Cas says. He glances back at the mouth of the tunnel. "That way. Voices— more than one person."

 

            When he looks back at them, he is met by the twin glares of Dean and Sam's head-lamps as they stare at him, the light white-hot and fierce in Cas' face; he lifts a hand to shield his eyes.

 

            For a long moment, Dean and Sam are quiet. Sam's hand drifts to his pistol at his hip, and he glances over Dean.

 

            "Don't look at me," Dean says. "I didn't hear it."

 

            Cas hears Dean's protestation for what it is: disbelief. Sam doesn’t answer, but his eyes are tracking over Cas' face, unconsciously mapping the lines of his expression, the set of his mouth. Cas has seen him do it countless times, quick and subtle as he studies a witness in some case they’re running.

 

            At last, Sam says, "Our guys or theirs?"

 

            "I don't know,” Cas admits.

 

            Dean huffs out his breath. "Well, we can't stand around here with our dicks in our hands. Either it's our guys, in which case, hooray, or it's whatever the fuck we're down here to kill, in which case, you know, job done. Either way, that," he says, and he points to the tunnel, "is our way forwards, and I'm sure as shit not having scaled down a thirty-foot drop like fucking Tomb Raider to turn back empty-handed now."

 

            Sam turns to Cas. "Can you hear them now?"

 

            Cas hesitates. "No."

 

            "Okay. We'll keep our ears on." Sam glances between Dean and Cas. "You all set? Good to go?"

 

            Dean taps his first two fingers to the rim of his helmet. "Aye, aye, sir."

 

            Sam leads the way, through one damp, snaking tunnel, and then other. At one time, the ceiling dips low enough that they stoop and bump the tops of their helmets against the rock, Dean grumbling the whole way about getting a bad back, Sam ribbing him gently from up ahead about sounding old beyond his years. Cas doesn’t contribute to the discussion—he won’t confess it to Dean or Sam, but he is still listening carefully to the silence around and behind them.

 

They reach a kind of lopsided T-junction at one point, hesitate and bicker momentarily about which way to go before settling on rock-paper-scissors. Sam wins—rock beats scissors—and they agree to bear left. Cas doesn’t mention the fact that Sam’s maps had promised a straightforward tunnel with little variety, no alternate routes, no tributary tunnels to become disoriented in. It will do them no good for him to pick at their situation; all they can do is keep going. He feels fear tighten in his throat, and he swallows past it.

 

He walks carefully here. Even with his headlamp, the dark washes everything out flat and punctures Cas’ sense of depth perception; it becomes hard to tell the difference between a ridge and a hollow, between an upwards-jutting rock and a sheer black drop—not until his foot is already decisively falling. They call out to one another—“Crevice here,” from Sam, “Hold up, watch your step”—their voices echoing in the small space and echoing to ring back to them and echoing.

 

Ahead, the path to the left narrows and narrows. They walk single-file, and then they tilt their shoulders, and then they flatten their backs to the wall and side-step, and then finally Sam huffs out his breath and says, “No, I can’t—this won’t work.”

 

Cas, in the middle, is trapped between the two brothers. He can’t move in either direction. He has approximately three inches of space either side of his chest and back, and he wonders, distantly, if it is possible for the rock to breathe and swell and compress tighter around him. He feels as though he can’t quite breathe.

 

“Wait, what?” Dean’s voice echoes sharply in the tiny space. His breath washes warmly over Cas’ ear. “What do you mean, _this won’t work_?”

 

“I’m pretty sure this is a dead-end,” Sam says. “Either way—I can’t fit. I don’t think any of us can. We’re gonna have to double back, take the other tunnel.”

 

“Jesus Christ,” Dean says, raising his voice. He doesn’t complain further, and Cas knows that he holds the law of rock-paper-scissors in bizarre, unquestioning reverence, but there is irritation in his voice nonetheless.

 

Cas turns to look at him, and his helmet bangs hard against the rock. The white light of his own head-lamp is reflected harshly off the water trickling down the rock in front of him, and for a moment, he is dazzled by the glare. He lifts his hands instinctively, a knee-jerk urge to push himself free of the wall in front, and he bangs the back of his helmet against the wall behind. He can’t move. He can’t get free—and to his other side, there is Dean, hemming him in, huffing and making a scene of his struggle to turn around, just to hammer home the point.

 

“Dean, move,” Cas says tightly. “Shut up and just head back.”

 

The theatrics stop immediately, to Dean’s credit. He looks back over his shoulder at Cas—near-blinding him in the lamp-light—and Cas can see concern in his face.

 

Cas closes his eyes against the blaze of Dean’s headlamp. He breathes evenly and he says, “Please. Please just move.”

 

 Wordlessly, Dean shimmies sideways until the tunnel opens up, and Cas follows him out. As soon as there is room to walk normally, Cas pushes past him and walks quickly, purposefully, back towards the other tunnel. If he moves fast enough, the rush of the dank, stagnant air past him feels almost wind. He can imagine, then, that he is out in the fresh, open air, not slowly suffocating in this black rot of a cave underground.

 

Sam and Dean follow. Their footsteps echo after him, heavy against the rock. Dean stays close by Cas’ shoulder, looks at him sometimes when he thinks Cas isn’t paying attention—as if the white heat of Dean’s lamp isn’t a clear indicator of it—and for a while, he is close enough that his hand bumps the back of Cas’ hand as they walk. The first time, it’s an accident. It makes Cas tense and flick a wary glance over his shoulder. The second time, Dean’s thumb grazes over Cas’ knuckles, and the tension bleeds from Cas’ shoulders. They don’t speak.

 

Up ahead, the tunnel curves, slopes downhill, and then, finally, widens.

 

It opens up into another, low-ceilinged cavern, some ten feet across, the floor unevenly sloping in pits and crags—and no tunnel through.

 

            Dean says, "You're fucking kidding me."

 

            "This can't be right," Sam says, and he lifts his flashlight to pan its thin white light over the walls, moving further in. "There's gotta be a way through. They can't have just disappeared."

 

            Cas remains near the entrance to the cavern, feeling the vague down-draft from the hole above his head pressing smooth and cold against his face. He turns his head to look up into it, past the twanging pink line they came down on.

 

            “We can get back up,” he says, his voice echoing eerily. He swallows. Its volume disturbs him. “Right?”

 

            “Yeah,” Sam says, tramping back to stand near him. “But I don't get it.” He passes Castiel, crouches down near the slimy, gelatinous puddle of skin, or whatever it is, at the bottom of the hole. This time, he doesn't touch it—just looks at it, gleaming sickly in the light from his helmet. “They came this way. They must have.”

 

            Cas glances over his shoulder, back to Dean, who is tramping around the perimeter of the low, bearing room, kicking with the toe of his boots against the wet, crumbling walls. Every dull _thud_ makes Cas wince. He wishes he would stop.

 

            He feels into his pocket for his phone, the familiar tangle of wires. He wonders what the brothers would say if he plugged them in right now. Just for a minute or two, to clear the heavy cave silence, and the things breaking it, from his brain.

 

            “Bones,” Dean says, suddenly, and Sam moves past Cas in a wash of cold air, and Cas follows.

 

            Their lamps land on what he's found, three beams converging—most of an animal, a young deer, perhaps—Cas can see a pelvis, a swathe of ribcage. All of it picked clean, glistening yellow.

 

            Slowly, Cas tilts his lamp up the wall, over its ripples and ridges, until he finds it.

 

            “There,” he says, pointing.

 

            It's an opening, like a shelf, cut into the rock. His light goes through it—inside, it's a tunnel, barely big enough to crawl through, barely wider than Sam's shoulders.

 

            Something inside glints.

 

            “Metal?” Dean says, angling his flashlight inside.

 

            Sam shrugs off his string backpack and hands it off to his brother, and before either of them can say anything, he's hoisting himself headfirst into the tunnel, one arm stretched out in front of him.

 

            For a moment, Dean and Cas stand, waiting, and Cas tries not to think of how much it looks as if the rock is swallowing him—and then Sam wriggles back out with a huge exhale, holding up something thin and curved in his hand.

 

            “Carabiner,” he says, dangling it aloft from one finger. “They went through.”

 

* * *

 

 

            The debate only lasts a few minutes, but to Cas it feels like hours—hours that they're talking, filling up space with their voices, intruding.

 

            Sam wants to go through. Dean doesn't think it's worth it. If any of them were alive, they were so far underground now, so far out of radio range, that they probably wouldn't ever come back up again. He points to their own dangling rope up ahead, their only way up from the bottom of this hole—“They came down, and they're trapped further inside. Who's to say we could even get back through that tunnel if we went through? They obviously couldn't.”

 

            Cas has no opinion. He leans against the wall beside the open tunnel, feeling occasional whisps of frigid air from inside.

 

            He thinks about climbing back up this crevasse in the dark, the way he'd come down. They only have one flare left, and they wouldn't use it here. Thinks about squeezing into this tunnel at his right, with no idea what's on the other side—angling himself forward on his elbows, the ceiling scraping his shoulders—they hurt, now, so many hours after Dean and the IcyHot, hurt from being cramped and tense and curled forward to fit through narrow channels and cling to a half-inch rope.

 

            Again, that feeling, that irrational thought— _I won't fit._

 

            He's never told anyone aloud, let alone the Winchesters, what he looked like, once. Jimmy knew. Pamela knew. A few others, empty corpses without eyes. But not these two—part of him is afraid they wouldn't understand. Part of him is afraid that he himself is forgetting.

 

            But he knows that he had had six wings, like every seraph, and if he tries very hard he can still remember how it felt to wrap them around himself, soft as steel, impenetrable. The most he has now are his own arms, limbs that aren't even his, to hug to his body—it's nothing, not nearly the same. And even though he aches, constantly, knowing that his wings are gone, knowing that the pain he feels is phantom and that nothing physical remains, knowing that there are no bloody stumps protruding from his flesh—even knowing, he still balks at tight spaces—he remembers the fall stripping them from his body, and he never wants to feel it again.

 

            “I'll go through,” Sam is saying, and Cas looks up at him, hearing Dean scoff somewhere in the dark. “If I can fit, we can all fit. I can radio back when I get to the end, if there is one. Okay?”

 

            “Sam.” Dean's voice drops, and he leans in close to his brother—Cas instinctively retreats into his own head; it's not for him to hear, though he hears anyway. “I know you want to find them. Okay? But we're not prepared to go any deeper. _You're_ not prepared to go any deeper.”

 

            “Dean—”

 

            “I know, you're feeling better, I know. But you think I don't notice?” Cas tries not to see him grip Sam's wrist, lift his arm up, clasp the crevice of his elbow. “You're still stick-fucking-thin, Sammy. The cold gets in your lungs. The docs didn't even want you doing cardio, let alone climbing down a goddamn hole—”

 

            “Since when did you give a shit what doctors say?”

 

            “It's not safe. Not for you, not for me and Cas. We should climb out. Regroup. Call in backup, something. You filed with the—”

 

            “Yes. And no, Dean. No—look.” Sam holds up the carabiner again. It flashes in Castiel's peripheral vision. “They went that way. A whole family. If it was one of us—”

 

            “It _isn't._ ”

 

            “But if it _was._ ”

 

            Cas keeps his headlamp trained on the ground between his feet, wet and coal-black and the same everywhere, its pitches and holes filled with brackish water. Any one of them could be a hundred feet deep, and they'd never know.

 

            The debate is over, and Cas knows without asking that Sam is going into the tunnel, and he can only hope he won't be required to follow after. He doesn't want to know what's on the other end. He wants to climb back up the anchored rope and get out of this cave, back into the chilly sunlight and the floral coverlets in the motel room, where Dean can help him with his shoulders and Sam can go for jogs. He wonders, fretfully, if they've gone too far already—something about being down here feels final, and it grates at him. He can barely imagine the sun.

 

            He stands up straighter, goes to them, if for nothing else than to be inside their voices, feel the faint warmth of their bodies.

 

            “What channel are you on?” Dean mumbles, trying to tune his handheld radio in the light from his helmet. Cas watches numbers flitter across the neon green screen, muffled static jumping out in shreds and pieces.

 

            “Three.” Sam is zipping up his jacket, re-tightening the straps along the bottom of his chin. “I promise I'll call back as soon as I find anything. Or don't.”

 

            Dean looks none too pleased with any of it, but he sets his radio, gives Sam a curt nod.

 

            Cas doesn't watch as Sam pulls himself by his arms into the narrow tunnel, hoists himself inside. He fiddles with the axe in his belt, running his fingers along the corrugated edges of the blade, meant for carving away at ice and rock. Dull, heavy, strong. An uneven weight at his hip. Next to him, Dean stands with his arms folded, clearly uncomfortable, tense as a taut string.

 

            There's an echo of a grunt from the tunnel, and when Cas looks up Sam is gone—there's a soft glow from his headlamp for a moment, a scraping of cloth on rock, and then silence.

 

            “Dammit,” Dean mutters, turning away sharply, looking down at his radio as if expecting to hear something already. He glances at Cas. “You okay?”

 

            “I'm fine,” Cas says, blankly. He doesn't know if it's true or not, but Dean is all edges of worry, and he won't add to it.

 

            “Sorry about earlier,” Dean says. “The flare and—the tunnel.”

 

            Cas gives him a weak smile.

 

            Together they crouch down on the floor, and then sit on it, facing the hole in the wall where Sam has vanished.

 

            “This is crazy,” Dean mumbles, after a while. He unclips his helmet and pulls it off, running a hand through his damp, matted hair. “You know, once—I was, like, twelve, maybe. Got in with this group at school. Bad kids.”

 

            Cas is grateful for the opportunity to look at him without the blinding glare of his head-lamp. He crosses his legs, tilts his head towards him.

 

            “They got into all kinds of shit, you know. And this one time—there were these mineshafts everywhere—it was Kentucky, I think. So anyway, one time they wanted to explore 'em. And I was twelve, or thirteen, maybe, so of course I went with them. We had maybe two flashlights. A couple of candy bars. I think they thought we'd find silver or something.”

 

            He laughs to himself, rubbing his face. He leaves streaks of dirt in the wake of his gloved fingers, and Cas listens. His heartbeat is keeping rhythm now, the way it's supposed to.

 

            “And we were just idiot kids. We found one—it looked pretty shallow from the outside, but it dropped off into just—nothing. Fifty feet in, just.” Dean gestures with his hand a straight drop, whistling softly. “All the way down. And this one kid said he was gonna try to _climb_ down. No ropes or anything like this. Just with his hands, on the girders.”

 

            His face goes still, his laughter gone.

 

            “He fell,” Dean says, eyes fixed on the tunnel up ahead. “Not far, not as far as we thought. But man—that split second—when his hands slipped, and he screamed. And the noise when he hit the bottom. Broke both his legs.”

 

            He shakes his head, grinds his teeth.

 

            “I've been in mines since then, but.” He puts his helmet back on, reignites the lamp. “Never forgot that.”

 

            That's when the radio creaks to life, and Cas feels a jolt of adrenaline up his spine as Dean fumbles to answer it, jamming the button down hard.

 

            “Say again, Sam?”

 

            “Body,” Sam is saying, through waves of static. “Body, body. You have to come see.”

 

            “Just come back, okay?”

 

            “You have to _see._ ” And the radio clicks over, jumps across a station, lands back on Sam but not before Cas hears—

 

            “Dean,” he says, heart in his throat with the pitch of a spoken voice lodged in his ear. Only an instant on a dying channel, soft enough that he could, perhaps, have misheard, but he knows. There’s no time to tell Dean, however, who is already on his feet, tightening the straps of his helmet.

 

            “Stay where you are,” he says into the radio, and Cas can't say anything about voices that he might have heard. “Okay? Sammy?”

 

            “Got it,” Sam says. “This is bad, man. I think it's Pete.”

 

            “Fuck,” Dean mutters. “Is it tight?”

 

            “It's a squeeze but you'll be fine.”

 

            “Cas?”

 

            “Definitely.”

 

            Dean turns to him, and Cas wants to violently say no—he doesn't want to go into that tunnel. He doesn't want to see what's on the other end. He doesn't want to know whose voice he's hearing.

 

            Dean is looking at him, intently, and very quietly he shuts off the radio, plunging them both into the silence at the bottom of the hole.

 

            “You're not fine,” he says.

 

            “We shouldn't be here,” Cas says.

 

            Dean swings his light to the tunnel, back to him.

 

            “We can't just stay here,” he says. “It could be Pete.”

 

            “He's dead,” Cas says, practically a whisper. “It's his body. We can't help him.”

 

            Dean kind of laughs, and it comes across as more mocking than he probably means. “What are you scared of?”

 

            It makes Cas' blood boil a little, hearing that—like he's some kind of shrinking violet, a coward. And he knows Dean doesn't mean it, can't mean it. But this, and the pain in his shoulders, the creeping under his skin in a quiet room—he's human now, and weak, and he hates every little reminder of that, every little reminder of how _nothing_ he is now.

 

            “I'm not afraid,” he bites back, and Dean's face sobers. “We shouldn't _be here._ It's not ours.”

 

            Between them, those last words ring upward, in concentric circles rising like smoke from a fire into the chambers above their heads.

 

            “Ours?” Dean repeats.

 

            Cas doesn't say anything. He sets his jaw.

 

            For a moment they stand there, at odds, and Cas tries not to think of Sam, alone at the other end of the tunnel in the silence, waiting for them.

 

            “We have to go through,” Dean says. “You know that, right?”

 

            “I know,” Cas says, with a bitter exhale. “But I don't have to like it.”

 

            “Will you tell me what's wrong?”

 

            “No.”

 

            “Okay,” says Dean.

 

            Another pause, another silence. Dean’s eyes move slowly across Cas’ face, trying to read him. Cas doesn’t know what he finds there. Then Dean turns off his flashlight, tucks it into his belt, where is clangs against the carabiners and the handle of his axe.

 

            He crosses the three feet to Cas and takes hold of his elbow, the way he had at the top, and finds his eyes under the rim of his helmet.

 

            “Hey,” he says, more softly than before. “You just follow my lead.”

 

            Cas nods.

 

            “You'll be fine. We'll all be fine.” Dean does something strange—he reaches up, touches Castiel's cheek, pulls his fingers lightly down his jaw. Eyes never breaking. “You trust me?”

 

            Cas nods again. There's a soft heat running down his throat, now, like hot water.

 

It's less of a surprise than he'd imagined, maybe—the kiss. Dean's head tilted, his face angled, his hand gentle where it curls beneath Cas' jaw. The soft touch of his mouth, the way he hears Dean's breath hitch in his throat when Cas presses carefully back into him. They've never kissed—never talked of kissing—maybe they'd never meant to—but it happens, a mile underground, like something that was waiting to happen, and had just been delayed a while. Cas' hands twist, without thinking, into the hem of Dean's jacket at his waist, and then it is over, Dean pulling away just far enough to breathe, the rims of their helmets knocking. Cas doesn't want to let go.

 

            “What was that for?” is all Cas can say, then, bluntly, and it makes Dean laugh deep in his throat.

 

            “For good luck,” Dean says, “I don't know.” His grin is broad, a little embarrassed, his touch still lingering, flat on Cas' shoulder now.

 

            Cas wants to say, _please, again._ His hands are still tangled in Dean's jacket. He says, "I wish you'd—" and doesn't know what to say after.

 

            "I will." Dean's voice is soft, earnest, sunlight-warm in the darkness. "For sure. Later. We'll talk."

 

            Cas looks at his mouth, almost by accident, and says, "I don't want to talk."

 

            Dean's grin curves wider. "Oh, so it's like that, huh?"

 

            Cas uses his hands on Dean's jacket to pull him slowly in—not quite for a kiss, but closer. "Dean."

 

            "Hey," Dean says. He tugs briefly on the hem of Castiel's jacket sleeve, affectionate. "Later. Okay? I hear you, but—not down here. We're gonna do this right."

 

            "You started it," Cas points out, and Dean laughs, despite it all—despite the dark and the quiet and the corpse on the other side of the tunnel—and he is all easy, golden warmth, in the midst of the cold black of the cave. Cas is helpless in the face of the way Dean rocks back a little on his heels and sways back in again, the light in his smile. Cas can't help the tiny bubble of amusement in his throat. "You thought—down here? Now? Today. And you—"

 

            "Okay." Dean shakes his head. The rims of their helmets touch dully, and Dean reaches up to adjust his light—it's been knocked out of place by the closeness of their faces. "Okay. Yeah. I started it."

 

            Cas loosens his grip on Dean's clothes. "We should go."

 

            "Yeah." Dean looks down toward his radio tucked inside his belt, up toward the tunnel. His hand drops from Cas' shoulder—grazes the length of his forearm, fingers sweeping just lightly over the back of Cas' knuckles—and then he sets his shoulders and turns to face the tunnel. "Here we go."

 

            Cas hovers behind him as Dean ducks low and crawls in. Then he's gone—he's pulled himself into the tunnel so quickly that Cas barely saw it. It hits him in the throat like a brick, and for an instant Cas feels a swell of panic, grabs at the lip of the rock and leans in, but Dean's already gone, a vague pinprick of light far away in the dark, a shuffle of body over stone.

 

            “Dean?” he calls in.

 

            There's no response.

 

            He's aware, too suddenly, of the vast, yawning dark looming over him.

 

            He doesn't let himself think about it. He plants one foot on the rock and hauls up, shifting his weight forward onto the floor of the tunnel, and Sam wasn't lying about it being a tight fit—his helmet scrapes the ceiling even as he's wriggling forward onto his stomach, elbows out in an army-crawl, and now he sees why Dean vanished so quickly—past the first few feet the tunnel slopes downward, and before he knows it his feet have cleared the cavern behind him and he's all the way in.

 

            For a moment Cas lies there on his stomach, and the sound of his breath is tight and close in his ears, pushed in on him from every side. If he lifts his head one inch, there's the ceiling; if he lowers it an inch, his chin is scraping dirt. He has half an inch on each side of his elbows at best.

 

            He closes his eyes, counts to ten.

 

            He can fit. He's flat, sturdy. Human. Human-sized.

 

            He can fit.

 

            One movement at a time.

 

            Slowly, he starts to crawl—shifting forward onto his elbows, pulling himself along. At least the rock is somewhat smooth, worn soft by centuries of water; his knees bump over ridges, and for a few feet he has to turn his head sideways, make himself as small, as thin as possible.

 

            It smells of cave fungus and wet, and his breath is so loud that he wonders if he's breathing correctly—feels a mounting anxiety—how much oxygen is in a place like this? And he can't even bend his elbows enough anymore—has to reach out to pull himself forward by his hands, fingers slipping on rock, through puddles of freezing water.

 

            How much longer is this thing?

 

            The ceiling gets lower—he can feel it skimming his shoulders when he lifts them to reach forward again—he's moving like a swimmer doing breaststroke, and the walls are closer now, he bumps his elbows on them with every movement, has to shimmy through inch by inch the narrower it gets.

 

            Cas hears himself begin to panic. _I can fit, I can fit,_ he says, over and over in his mind, but it isn't helping. His breath is getting faster, his jacket is rucked up and he can feel rock scraping against his bare hip, his heart is pounding—ahead is only dark, dark and the narrower passage, and no sound except him, alone.

 

            “Dean?” he calls, and his voice sounds incredibly small past the blood that's beginning to pound in his ears.

 

            He hauls himself forward a little more, thinks he sees light up ahead—and yes, it moves, it must be the end.

 

            “Dean!” he calls again, and this time Dean responds.

 

            “Cas?” His voice bounces through the tunnel, watery and thin. “You're almost out.”

 

            “I'm—”

 

            He sees the lights—he has a handful of stone in his grip, enough to yank himself forward with. But the rock is snug around his hips, across the back of his right leg.

 

            He can't move.

 

            “Dean,” he says, pulling, trying to edge his way out and down. “Dean—”

 

            “What's wrong?” Sam's voice, heady with concern.

 

            “I think I'm stuck,” Cas calls back, and he hates how scared it sounds. His throat is numb, his heartbeat a thud against the ground. “I can't—my leg is stuck—”

 

            “Hold on,” Dean shouts in, “I'm coming back. I'm coming back in, Cas. Stay still, okay?”

 

            He tries to dislodge his leg with his left foot, but nothing happens. The cave wall only seems to rub closer.

 

            Then, the beam of Dean's light, the sound of him moving over rock, up the tunnel to Cas. It's narrow, uncomfortable, and when Dean comes within arm's length he's panting. He reaches out, and Cas fumbles his fingers forward enough to grab onto Dean's for a split second before they come apart again.

 

            “What's stuck?”

 

            “My leg. My hips.”

 

            “Okay.” Dean lets out a long exhale. “Okay. Don't freak out, okay? Just relax. Find room to move. Can you—kind of turn onto your side—”

 

            Cas shakes his head. His helmet hits the side of the tunnel. He swallows, trying to find the rhythm of his breath again, but it's not there—his chest is tight. He wonders if he's suffocating.

 

            “I can't,” he says, almost afraid to speak, to lose precious air. “I can't move—”

 

            “You can. I know you can get through there. Sam and I did. Yeah?”

 

            “I—fuck. Fuck—”

 

            “Cas? Breathe. Breathe, okay?”

 

            “There's no room—there's no room. There's no room.”

 

            “There has to be. Can you back up? Can you—”

 

            “I _can't._ ” He can hear himself wheezing now, and it's totally unknown to him, the squeezing in his chest, the squeezing all around him, he wonders if the tunnel is getting narrower somehow, pressing on him, flattening him—

 

            “You have to calm down, dude.”

 

            “I—I—”

 

            “Breathe. Listen to me. Listen to me, yeah?” Dean shoulders forward a little more, manages to grab onto Cas' wrist, pull it forward a little. Cas fumbles for grip, finds it. He can only see a sliver of Dean's face in the light—a slash of green eye—it's fixed on him. “You're gonna get out of this tunnel. There's an exit down-mountain, remember? That's what Sam says. We don't even have to come back this way. Are you listening to me?”

 

            Cas nods, though his head is buzzing.

 

            “Good. Keep listening to me. Move your hips forward as far as you can. Hey. How about that back there, huh?” Dean laughs a little, hoarse and breathless. “I mean, I can't give you an A for kissing, but it was kind of a pop quiz, after all—”

 

            Cas gently shifts his hips, and they do bump a little forward, painfully, over a ridge in the rock—his leg is still trapped, knee boring into the ground, but he's an inch closer to Dean, and he can sort of move his other leg to the left.

 

            “We'll work on it. I bet you're a natural.” Dean shifts himself backward, leading Cas' arm out long, and Cas bites his lip, tries again, feels rock biting into his thigh, knows he's not making it out of here without a rip in his clothes at the very least. But Dean is closer than before, his light harsh in his eyes. “Look. It's gonna drive Sam crazy when I tell him how good of a kisser you are. I'm not gonna shut up about it. Been waiting too long, yeah? Yeah—a little more. Where's your leg?”

 

            “Almost—”

 

            “You got it. Come on. Hey, I'm gonna buy you dinner. Not at Biggerson's. Somewhere else. Someplace with napkins, huh? And you won't even owe me.”

 

            Finally, Cas feels the rock give, and his leg comes free—he slides a little down the final slope of the tunnel, almost knocks lamps with Dean, and Dean laughs, pleased, cramps Cas' arm up next to his chest and squeezes his hand tight.

 

            “See? That wasn't—”

 

            There's a noise like a gunshot, and both of them freeze.

 

            Dean doesn't take his eyes of Cas, and Cas doesn't look away, either.

 

            “Sammy?” Dean calls back, very carefully. “Was that you?”

 

            “Was what—”

 

            They don't hear what he says.

 

            Cas feels the sudden pressure on his helmet before he sees the dust rocketing from the ceiling of the tunnel, sees bits of stone crumbling down over Dean's face. Another crack and a weight on Cas' spine, and a rumble high up above them—

 

            “Fuck. Fuck.” Dean looks wildly up toward the ceiling and then his eyes swivel back to Cas. His grip tightens, hard. “Okay. Fuck—move.”

 

            Cas is still frozen for an instant, and Dean is, too, until there's a crash at the far end of the tunnel, and the rumble begins to climb, rapidly, from the cavern with the rope, like a train barrelling through the dark—

 

            “Move! Move!” Dean shouts, and he yanks hard on Castiel's arm, and Cas propels himself forward after him, knees scrambling over rock, elbows biting into the shivering tunnel walls, and Dean is still screaming _move!_ when Cas tumbles facefirst out of the tunnel and into the floor of the chamber and dust and rock screech out of the channel after him, stone cracks and crumbles and roars as it falls, Cas rolls to his knees and feels out blindly for Sam and Dean and finds their frantic bodies with his hands in the blackness, and when he shoots his light up over the wall the tunnel is a maw of sealed rock, and the exit has vanished.

 

            The tunnel is gone.

 

            Cas is left, half-sprawled, on his ass in the dark, one knee pulled up in front of him, staring vacantly at the wall. He waits and waits for the reverberations of the cave-in to stop, his heart pitching nauseatingly fast and hot into his throat as the walls, and then there is the steady touch of Sam's hand to Cas' shoulder, and Cas realises that he is the only thing shaking.

 

            "Cas?" Sam drops into a crouch, tugging at him worriedly. The glare of his head-lamp through the floating dust is so bright in Cas' eyes that all his vision is washed out into searing white, and Cas only sits there and looks into it, still trying to breathe. "Hey. You made it. You okay?"

 

            "No, he's not fucking okay," Dean snaps, and his voice shatters hard off the walls that press in close around them, rings out sharply like stepping on broken glass. "He's not okay—he nearly got fucking crushed. I told you. I _told_ you, we're not prepared for this. And—now what?"

 

            For a moment, in the noise of their breath, all three of them stare at the wall they came through.

 

            Cas, on his knees, reaches forward a little, touches the nearest stones with his fingertips. He doesn't need to pull on them to know they're stuck in fast, that the tunnel is sealed, that there's no way back.

 

            "Now we keep going. There's another exit," Sam says breathlessly, lifting his head to look up at Dean. Cas, on the floor, blinks as the darkness of the cave rushes back in towards him. Faint spots shift in the corners of his vision. "We're not trapped."

 

            "What Indiana Jones bullshit is it going to take for us to realise that this is too dangerous?" Dean snaps. "Cas nearly broke both his legs earlier. Now he nearly gets crushed alive in a goddamn cave-in, and we're just gonna keep going, until, what—one of us falls down a hole, or gets impaled on a stalagmite, or the cave comes down again--"

           

            "Okay, Dean," Sam says, harsh and abrupt, "let's go back. Show me how."

 

            Cas' eyes slowly adjust to the inconsistent light of the cave—the oppressive blackness on all sides, the dancing of their head-lamps across the stone, the walls found and lost and found again in the changing light—he comes to focus on what is behind Sam.

 

            He'd almost forgotten.

 

            From a distance, it is hard to tell exactly what has happened to Pete Harrison. He is a broken, indistinct shape. Cas is staring, but he can't quite reconcile the smooth, rounded edges of a human as he expects to see it with the fractured imprecision of the body. He moves, climbing unsteadily to his feet, past Dean and Sam, who go on arguing until Cas cuts between them at a halting pace. They turn to follow him, and the beam of Cas' head-lamp falls on what is left of Pete.

 

            Dean says, "Jesus."

 

            The body is torn uncleanly open from throat to pelvis. The yellowing points of his shattered ribs protrude, splayed wide like an unhinged jaw; whatever tore his chest open used such force that it snapped his spine, and he arches sharply away from the puddling rock. Cas imagines it—hands into the sternum, twist and pull. The cavity left behind is enormous, a messy, gut-wrenching tangle of grit and gore: excessive, for going after a heart. His legs curl underneath him at impractical angles; his ankle, in particular, almost folds back on itself. His mouth is slackly open, his face smeared with blood but otherwise untouched. His fingers are ragged, bloody stumps, fingernails loose and broken from some attempt at escape.

 

            There is mud in his eyelashes.

 

            Cas drops into a crouch next to Pete, scrutinising the knot of his eviscerated torso, misplaced meat.

 

            "No sign of Kurt and Sue?" Dean asks. He seems sobered, suddenly, by the sight of the body they crawled down here to see.

 

            Sam shakes his head. "No. And the battery on his radio is dead, so—"

 

            "Shit," Dean says.

 

            "I don't think this is a shifter," Sam says, his voice hushed with concern, as though he doesn't want to voice what they are all thinking. "Shifters don't act like this. Werewolves either."

 

            Cas sifts his hand carefully through the mess, fingers turning over the bruised and battered remains where they puddle in the over-large cavity now.

 

            Behind him, Dean makes a revolted noise in his throat. "Cas, what the fuck are you--"

 

            "Nothing is missing," Cas says.

 

            For a moment, Dean and Sam are silent. Then: "What?"

 

            "Whatever did this was looking for something," Cas clarifies. "And it didn't find it." He straightens up, wipes his fingers on his pants. "It hasn't taken anything from Pete's body—he's intact."

 

            "Loose definition of intact, maybe," Dean says.

 

            Sam frowns. "Why open him up if you're not gonna take anything?"

 

            "Perhaps it was interrupted," Cas says quietly. He stretches out a hand to close Pete's eyelids. "Perhaps he wasn't good enough."

 

            Then he reaches over and unclips Pete's carabiner, takes his length of rope, his climbing axe. Pete isn't going to need it.

 

            Dean stands up, dusts his hands off on his jeans. "Okay," he says. "Well, Pete's fucked. So what now?"

 

            "We keep going," Sam says, slowly, turning his head toward his brother, as if coming out of a trance. "There's another exit, if what Pete found on recon is right. It's a little further around the base of the mountain, downhill towards the river, so it's going to feel like we're just going deeper and deeper, but it's the only way out."

 

            “I thought they said no one had ever been down here before.”

 

            “No,” Sam says—Cas can barely detect the shiver in his voice. “They haven't.”

 

            “So there _could_ be an exit,” Dean says, flatly. _“Could._ That's real reassuring.”

 

            Sam ducks his head, swallowing.

 

            "And the Harrisons?" Cas asks.

 

            Dean looks down again at Pete. The light of his head-lamp glints yellowly from the ragged edges of Pete's ribs. Dean's hand plays, distracted, over the metal head of his climbing axe.

 

            "I get the feeling we're gonna run into them sooner rather than later."

 

            "We should move," Sam says. "The longer we stay down here, the harder it'll get for us to keep going."

 

            Sam doesn't clarify, but he doesn't need to. Cas, in his newness to being human, has an uncomfortable, consistent awareness of how frequently humans need to eat in order to function properly; he knows that they only have one day's emergency food rations in their backpacks to keep their energy up.

 

            Cas adjusts the straps of his pack, checks his helmet, and he says, "Lead the way."

 

            "You sure you're okay?" Sam asks.

 

            Cas will be okay, truly, when he's out again in the sunlight, when he can breathe. Hunched in the dark away from the narrowing darkness, he can feel the old cramping pain flare hotly at the base of his neck and in his shoulders, a dull throb that he can feel in his sternum and in every movement.

 

            "Fine," he says, climbing to his feet. "Let's go."

 

 


	2. Chapter 2

There is only one way forward. Dean sets off first, ducking his head under a low outcropping of rock; Sam extends a hand for Cas to follow after. Ahead, the tunnel tapers, but Cas sets his jaw against the irrational fear that flickers coldly in his gut, and he walks. The ground is unsteady underfoot, sloping first one way, then another. There is a persistent, slow drip of water somewhere - above them, behind, somewhere ahead: it's impossible to tell as the noise echoes and echoes—and it beats, just slightly off-rhythm, inside Cas' skull, until he can feel a headache pressing in behind his eyeballs.

 

            The tunnel widens after a time, tilts unevenly downhill, and Sam, Dean, and Cas pick their way carefully down, slipping in puddles and in rock worn smooth by time. Their head-lamps throw long, shivering shadows in the blackness, panning side to side as they check out their surroundings.

 

            After some ten minutes or so, walking in the dark, Dean stops.

 

            "Look at this," he says, his voice low.

 

            Cas turns his head to follow, and he sees what is caught in the beam of Dean's flashlight— another corpse, this one old, unidentifiable; the skin has shrivelled and the muscle has wasted on the bone. The face has collapsed like old fruit, eyes sunken and dark; the hair is long, coarse, fair, tied in a high ponytail.

 

            She's out of reach, draped over the edge of a smooth, shallow cliff ten feet above their heads, staring down at them like a gargoyle. But even at this angle they can see—just like Pete, her ribcage pried open, resting on the lip of the cliff, her insides a black, mouldering snarl, dripping like molasses down the side.

 

            One arm hangs loosely, tethered only tenuously to shoulder, and crooked fingers curl into nothing.

 

            Dean says, darkly, "You think she was good enough?"

 

            Sam says nothing. They move on.

 

            They keep walking through the dark, through the labyrinth. There are occasional holes in the walls, crevices—not tunnels proper, but crawl-spaces. They stick to the main path.

 

            Eventually, the passage opens up a little, twists, then splits. One way tilting away, deeper and darker; the other unevenly sloping sideways, curving out of sight.

 

            Sam fumbles in his pocket for his lighter, brings it up into the centre of one tunnel away—the right—and flicks the flame on. It burns steady, hot and yellow to cast a warm light on Sam's face.

 

            Before Sam can move to test the flame on the other tunnel, Cas hears it: the soft shush of distant voices, swelling one over another as though in conversation.

 

            He says, "Left."

 

            Dean and Sam both look at him. The paired light of their head-lamps makes Cas wince a little, his headache pulsing fiercely in the dead centre of his forehead, and he leans back, tilts his head away to escape the unfriendly, blazing white.

 

            Sam clicks the lighter off.

 

            "Voices?" Dean asks. His voice is faintly guarded—not defensive, but careful. Staring down the head-lamps, Cas can't see his face.

 

            Cas says, "Yes."

 

            "To the left?"

 

            "Yes."

 

            Dean and Sam exchange a wordless glance, but Cas can read their uncertainty in it. _Do we believe him?_ Dean says in the set of his shoulders, Sam in the crease of his brow. _Do we ignore him?_

 

            "I think you've got better hearing than us," Dean says, straight-forward and sensible, but his transparent attempts to justify his belief in Cas only serves to irritate him—as though they can't just trust him. "Leftover, maybe, from before. You know."

 

            "Yeah," Sam agrees, but tenuously. "That makes sense."

 

            Cas sets in first, taking the left branch of the tunnel. He hears Sam and Dean coming slowly after him, the clatter of their gear against their legs echoing in the dark. Cas puts a hand out to the cold, wet wall, feeling along its bumps and ridges, one step at a time into a half inch of frigid water standing on the floor.

 

            They make it less than fifteen steps when, as though on an echo, Cas catches a fragment of broken melody. He becomes still.

 

            It is gone so quickly that he thinks he must have imagined it, but Cas thinks he is not imaginative enough for that—for the slow, lilting music in calando that now echoes in his ears.

 

            A few discordant notes, and they play over in his head. He couldn't make that up. He turns to look back, towards the other tunnel.

 

            Up ahead: "Cas?"

 

            Sam and Dean have passed him, in the instant it took to pause and listen—Cas blinks, disoriented. He doesn't move to catch up.

 

            His head-light shimmers and fades into the dark, its beam not reaching for enough to pick out the edges of the other way, the curve of the walls. He is listening.

 

            "Cas?" Dean's voice is too loud in the narrow space, fracturing like glass, recoiling from every wall and filling Cas' ears. He is losing the music. "You okay?"

 

            "Quiet," Cas says, just softly, but the darkness and the hard wet rock carries his voice for him in fragmented echoes. "I'm..."

 

            Dean moves back towards him, a disembodied voice and a white light, his silhouette bleeding out into darkness. His footsteps ring out, his boots heavy and dull against the stone. He reaches out for Cas, settling a tense hand on his shoulder. "Cas, what are you doing?"

 

            "There was," Cas says, and loses the words halfway through, still focused on the ebb and flow of the silence around them, "something."

 

            "Okay." Dean's voice is slow, tentative. His fingers tighten on Cas' shoulder. "I mean. Could we get a little more specific than that, please?"

 

            Cas' mouth is open, the words caught somewhere behind his teeth.

 

            "Singing," he says, at last, and he looks back at Dean, and Sam, worried, just behind. "It sounded like singing."

 

            In the dark, it is hard to pick out Dean's expression, but he doesn't answer, and his disbelief is palpable.

 

            Sam says, "Singing?"

 

            Cas steps back, away from their scrutiny. “You don’t believe me.”

 

            "Cas." Sam's voice is quiet, diplomatic. "Do you think maybe you've been spending too much time plugged into your—"

 

            "This has nothing to do with my white noise," Cas snaps. "I know what I heard."

 

            "It can really screw up your head,” Sam says, gently. “I'm not suggesting that you're making it up—"

 

            "Just that I'm imagining things." Anger curls hotly beneath Cas' skin, curls his hands into fists. The idea is more offensive than if Sam had accused him of fabricating the voices. Lying would mean a kind of destructive self-awareness; Sam's suggestion, instead, is that Cas has no control over his own senses, that he's somehow unstable and can't tell what is and isn't real.

 

            Cas thinks, unwillingly, of Naomi, of the cold slide of intrusive metal beneath his eyelid, of being unmade.

 

            "I know what's real, Sam. This is real. There is something down here beside us and it is—"

 

            "Starting up a fucking karaoke night, apparently," Dean interrupts. "Cas, man—come on."

 

            Cas turns on him. "You believed me earlier."

 

            "Yeah," Dean says. "I did."

 

            “And?”

 

            “And—Cas, no one is down here,” Dean says, exasperated. “Pete's dead. Kurt and Sue are probably dead, too. Whatever killed them sure as hell isn't singing in the shower, and if it is—I don't wanna stick around for the concert. We have to keep moving. We can't stop to listen every time you think you—”

 

            “We don't know what it is,” Cas snaps. “We don't know what it does. I _do_ know what I hear.”

 

            Dean opens his mouth to retort, but sighs, lets it drop. Looks at him, Cas presumes, from beneath that hot white glare on his skull.

 

            “We can't hear it, Cas,” Sam says, very softly, from further up the tunnel. “Maybe you're picking up on something we can't sense. You know? I wouldn't be surprised.”

 

            Dean doesn't say anything. Cas has an ugly feeling that he doesn't agree. It gives him a nauseating feeling—like betrayal, almost—he can still feel the warmth of Dean's mouth on his, and now they're at odds like this, standing aslant in the tunnel.

 

            “Doesn't matter,” Cas says, finally, straightening his spine. “We need to get out. Right?”

 

            He shoulders past Dean, more roughly than he means to, and Sam tries to comfortingly catch his arm as he passes, but Cas slips from that, too.

 

* * *

 

 

            They pause in the next chamber to catch their breath, to drink water and eat something from their packs.

 

            Cas isn't hungry. There's a gash on the back of his leg from the cave-in that he hadn't noticed until it began to sting half an hour ago. He doesn't mention it—doesn't want either of them fussing. Instead he folds up one of his gloves and stuffs it into the rip in his pants, against the flesh, to soak up the blood and keep pressure on the wound.

 

            The brothers have turned off their head-lamps in favor of the flashlight on the floor. All of their eyes are aching by now, Cas knows, from the high flashing contrast. He's grateful for the dimness.

 

            His shoulders hurt and his pride is wounded, and all he can think about, crouching on the floor, is the motel room with its floral coverlets, and the TV wired unsteadily into the corner of the ceiling. Besides the bodies, they've seen nothing here; if not for the noises, if only the ones that Cas can hear, they're not welcome. He just wants to be out. Done with this.

 

            He watches Dean from a distance, twisting and untwisting the cap of his water bottle, looking wearily at nothing. He moves his foot, knocks against the belt full of gear that he's taken off to rest, and the loud metallic noise of it shoots up and around and through the air, and Cas winces.

 

            Sam is halfway through a granola bar when he lifts his head suddenly, facing the outward passage.

 

            “Did you—”

 

            Dean and Cas meet eyes for an instant before they hear it, too.

 

            This time it's not just Cas—it's a voice that echoes unsteadily up from ahead, a male voice, twisted and weak, calling.

 

            Sam looks at them, wildly, and Cas nods, and before he can really properly get to his feet all three of them are scrambling for the passageway, flicking their lamps back on.

 

            A few more feet in, the voice takes on clarity—Cas can't help but feel a chill of relief at its physicality, its trueness: a male human voice, calling desperately and hoarsely for help.

 

            It's Kurt Harrison, somewhere up ahead, and he's alive.

 

            They move in silence towards the voice, following its echoes on the walls. Cas knows they don't want to call back in case it's something other than they expect. For a few minutes all Cas is aware of is his own breathing, the tamp of his boots on the cave floor, the rhythmic beat of Kurt's voice in the tunnel, the swivelling light of Sam and Dean's lamps ahead of him.

 

            And then, without warning, Sam stumbles to a shaky stop, and Dean barely keeps from bumping into him, and Cas stalls behind him in turn, close enough to feel the warmth coming off Dean's back.

 

            The floor has dropped out again, and Cas can see the vague suggestion of walls far away—a huge open cavern just below their feet.

 

            Sam gets carefully to his knees, and then Kurt's voice comes again, so loud that it almost startles Cas—“Help! Somebody!” And Sam's light must flash over him somewhere down there in the dark, because no sooner has the voice begun bouncing off the walls in its endless echo than Sam is scrambling for a handhold on the rock to get down to him.

 

            It's not a long way down—ten feet—and Dean and Cas follow in such quick succession that Cas hardly registers the movement down. His head is a blur of head-lamps and noise and when his feet hit the floor of the cavern it's as if cold, sharp reality comes rushing back, like a smack in the face, and he comes to surrounded by bones.

 

            He freezes.

 

            Sam and Dean have already converged on the weeping, shivering shadow in a far corner that must be Kurt Harrison, alive against all odds, incredible, and Cas should follow after. But he can't move.

 

            He is motionless, transfixed by the mass grave that they have inadvertently stumbled into.

 

            The bones are unclean, blackly spotted where meat has hardened in rot. They still fit into their joints, whole segments of bodies roughly hewn apart and then abandoned.

 

            Whatever is down here is not eating its victims. It is searching for something.

 

            Under Cas' left foot is a human scapula, shattered under the weight of his landing. Some feet ahead of him, the beam of his head-lamp falls on a skull.

 

            It is face-down, the frontal bone smashed almost beyond recognition. The head resembles a crushed egg-shell more than something belonging to any once-living person.

 

            At the base of the skull, the spine is broken, wrenched out of alignment; Cas' gaze follows the path of that spine, the glare of his light glinting on brown bone, and he finds the ribs, the arms, the pelvis.

           

            The body is intact.

             

            "Cas? Cas!"

 

            Cas lifts his head.

 

            "Jesus—do you want to give us a hand here?" Dean's voice is snappy, irritated, and far, far too loud. "Come on!"

 

            Cas glances back down at the skeleton—the lone whole body he has seen so far—and he steps carefully over it. He feels unsteady, off-balance, picking his way through the bones that shift and crack under his boots. His own breathing seems to echo in the dark. He can hear his pulse in his ears.

 

            Pressed back against the far wall, huddled into himself, is Kurt - shaking, pale-faced under the harsh light of Dean and Sam's head-lamps. The bone in his ankle is snapped cleanly in two; Cas can see it pushing whitely at his skin. He has a head wound, his hair matted with tacky, dark blood.  He has one blown pupil, his eyes bloodshot and black and staring. In all the flickering light and jumping shadows, he looks more like a ghost than a man.

 

            "I—I—" he is saying incoherently, as Sam and Dean crouch beside him, Sam checking his pulse, Dean helping him to get his arms out of his backpack straps. "I'm—I—"

 

            "Hey, it's okay," Sam says, his voice low and reassuring. "You're gonna be fine. Tell us what happened."

 

            "They—" Kurt's voice cracks. "I was—I hid. When they—" His breathing breaks up, laboured, in panic, and his eyes dart, rolling in his head, to look past Dean and Sam. His gaze land on Cas, standing behind them, and he lets out a gut-wrenching sob.

 

            "Take it easy," Dean says, and he has a comforting hand on Kurt's shoulder, squeezing, as Sam shoulders out of his backpack to search for supplies. "Take your time, man. We're gonna get you outta here."

 

            Kurt curls forwards into himself, his grimy, blood-smeared hands clenching reflexively around his knee. "My mom," he chokes out. "They grabbed my mom. They—"

 

            His words break off into a shuddering, strangled noise. He shudders and shakes and for a moment, there is only the desperate, gulping gasps as he tries to steady himself. His hunched shoulders tremble; his fingers jitter wildly. He is incoherent, and Sam and Cas exchange a look over Kurt’s head.

 

“Hey, you’re okay, Kurt,” Sam says, pulling out his medical supplies. “We’ll find your mom. We’ll find her, I promise. All that matters for now is making sure you’re alright and getting you the hell out of here. Okay?”

 

Sam smiles at Kurt, warm and reassuring, but it’s lost on Kurt, whose face is buried in the crook of his elbow.

 

His voice is a feverish whisper when he says, "They're gonna come back."

 

            Sam stops.

 

His eyes find Cas’ again, then drop to the supplies that he has fished out of his backpack—an Ace bandage, a splint, a spare pair of hiking socks. In a voice that is carefully soft and unthreatening, Sam says, “Kurt, what are they?”

 

            "I don't know. I don't know. I don't know, I don't—"

 

            "Alright. Okay, it's fine. Don't worry about it." Sam starts unrolling the Ace bandage. “I’m just gonna focus on patching you up, alright, but—Kurt. Look. I'm gonna have to do something with this ankle of yours, or we're not gonna be able to get you out of here. This is gonna really hurt, okay? But I've gotta do it. I've gotta do it to get you out of here. You with me on this?"

 

            Kurt nods shakily.

 

            Sam lifts his head. "Dean, can you go stand watch? Cas—give me a hand."

 

            "I can stand watch," Cas says.

 

            Dean slaps a hand to Sam's shoulder, uses the grip to lever himself to his feet.

 

            Sam hesitates. He says, "No, it's—it's okay, Cas. Dean's got it."

 

            Dean reaches that same hand for Cas as he passes—hesitates—brushes fingers over Cas' arm, and then pulls away. He unholsters his pistol, thumbs the hammer; his other hand drifts warily to the climbing axe at his hip, and he moves back into the main body of the grave.

 

            Cas moves past him, slow and unsure, to crouch at Kurt's side.

 

            "Here." Sam passes Kurt the bundle of clean socks. "You're, um. You're gonna wanna bite down. Cas? Can you get in here, hold him still?"

 

            Cas crawls in closer. He presses one hand to Kurt's shoulder to pin him back against the wall, the other to Kurt's thigh, just above the knee.

 

            Sam waits for Kurt to be ready, and then he starts.

 

            He unlaces and removes Kurt's boot; he tucks the metal splint alongside Kurt's swollen ankle, and carefully lifts his foot to wrap the bandage around tightly.

 

From the first contact, Kurt screams.

 

            The sound of it is shrill and deafening, even with the sock stuffed into his mouth, and it fractures off the walls, bouncing in glass-sharp echoes, and the sound goes on and on and on. Dean jerks back to look at them, lamp-light swinging, and Cas flinches, his hands tightening on Kurt to hold him still as he jolts and struggles and sobs.

 

            Sam says, "It's okay, it's okay, just breathe, I'm nearly done—" as he lifts the foot higher, wrapping the bandage around again, and Kurt lets out a hollow, agonised sound that Cas hears threefold in the small, dark space.

 

            Under the sound of Kurt's sobbing, Cas says quietly, "I found a body that I think they rejected."

 

            Sam doesn't look up, focused on the task at hand. As he carefully wraps Kurt's foot, he murmurs, "What do you mean?"

 

            "They didn't open it up. Just left it there."

 

            Sam's eyes flash up to meet Cas'. "What was wrong with it?"

 

            "I don't know." Cas pauses. “The head was smashed in.”

 

            The look Sam gives him is troubled, unsure.

 

            He fastens the end of the Ace bandage, smoothing out the gauze to make sure it's comfortable and secure, and then he sits back on his heels. "There. Good as new."

 

            There are beads of cold sweat collecting at Kurt's hairline, glistening over the crust of dried blood. He spits out Sam's hiking sock, scrubs the back of his hand over his mouth, and says, in a voice that is low and strained, "What did you find?"

 

            Sam exchanges a glance with Cas, then drops his head to focus on packing away his first-aid kit.

 

            Kurt is quiet when he speaks again. "My mom—"

 

            "We haven't found your parents yet," Cas says.

 

            Sam becomes still.

 

            "We've been following your trail, but I'm afraid there's no sign of them," Cas says.

 

            Sam says nothing. He finishes rolling up the leftover Ace bandage, pushing it and the rest of his supplies back into his backpack.

 

            Cas lets Kurt go and hauls himself up onto his feet. He's tired - his calves ache from walking and climbing, and his shoulders are locked so tense that there is a sharp, shooting pain at the base of his neck whenever he turns his head too far. Cas watches as Sam fishes a granola bar and a bottle of water out of his backpack to hand to Kurt.

 

The cavern is almost silent now, save the crunch of bones under their feet. Cas tries not to look at them. He focuses on Kurt.

            He's been down here almost forty-eight hours, he realises. Who knows how many of those hours were spent alone, in the dark, crippled—he wonders if Kurt could hear it, too, the off-kilter songs of the things that killed his father and everything under his feet. The whispering.

            He almost bends to ask, but thinks better of it. Sam and Dean already think he's crazy. He doesn't want this strange boy thinking so, too.

 

            Bone fragments shift and crumble as Dean comes back to them, and Cas shields his eyes with a hand, the glare of Dean's head-lamp dazzling.

 

            "How's it looking?" Dean asks. He has his pistol in his right hand; he lowers it, but he doesn't take his finger off the trigger.

 

            Sam lets out his breath between his teeth. "Uh." He pivots, away from Kurt, towards his brother, and scratches his head beneath the rim of his helmet. "I gave him some food and water, some painkillers... I got a splint on his ankle and wrapped it up, so it's not gonna get any worse, but—it's bad. He's not gonna be able to put any weight on it."

 

            Dean nods once. "Okay. Great." His words are flat. "Sam, how the hell are we gonna get him outta here?"

 

            Sam doesn't look at him. "I don't know."

 

            Dean steps in closer, dropping his voice quiet. "Tell me if I'm wrong here, but he can't walk, he can't fight, he can't climb—hell, I'm willing to bet he can't even crawl without crying—"

 

            "Yeah, okay, Dean, I get it."

 

            "I mean, what are we supposed to do—piggyback him all the way up?"

 

            Their whispers tangle together, incoherently shush and swirl through the dark. Their voices fade. Underneath their feet, bones shift and crack.

 

            Cas stares down past his boots, at tibia, patella, femur, loosely strung together with rotting tendon. He thinks of this body - his own body, now - and what it looks like beneath the skin, once he has been hewn apart and pried open and—

 

            "What, so you wanna leave him here?" Sam hisses.

 

            Dean recoils. "Jesus—of course not, I'm just—I'm just saying, okay—"

 

            "Yeah, you've made your point. Look—we have to keep going, and Kurt is coming with us. We need solutions, not more problems."

 

            Dean rubs a hand down over his face. He sighs. "You tell him about Pete yet?"

 

            "No." Sam hesitates, glances back, but Kurt isn't listening. His face is buried in his knees. "Cas lied to him. Said that we hadn't found them."

 

            Dean turns to stare at him. "Dude."

 

            "So far Kurt has demonstrated himself to possess little to no mental fortitude," Cas says sharply, keeping his voice low. "Forgive me if I don't want his grief to impede on our survival."

 

            Dean and Sam are silent for a long moment, and Cas can feel their petty, sentimental judgment. He waits for one of them to try to argue that Kurt won't slow them down, but they have sense enough at least to recognise that, it seems.

 

            "Okay," Sam says, slowly. The look on his face has shifted—a different trouble, now. Cas can't help but feel that it's directed at him. "How are we going to do this?"

 

            Dean straightens up, shifts the straps of his backpack on his shoulders. "Right—we'll have to take turns supporting him. Team Kurt will go in the middle so that the others can cover them if anything comes up. We can rig up some kind of carry harness if we have to climb—or, worst comes to worst, I'll fireman-lift the guy and do it the old-fashioned way."

 

            Cas recalls the straining of the rope under his weight, the groan and creak of it where it had rubbed over stone when he was swinging, weightless, in the dark. The rope won't support two people. He knows from experience, however, that his pragmatism is rarely appreciated. The Winchesters are idealists.

 

            They want to believe that everyone can be saved. More and more down here, Cas just wants to live.

 

            Dean volunteers to be the first custodian of the casualty, and he eases Kurt carefully up onto his feet, slings Kurt's arm around his neck, and steadies him with a hand on his waist. The cavern is large enough that the walls disappear into the dark in any direction, and so Sam leads the way as they grope along the edge of the cavern in search of their next way forwards.

 

            They find one tunnel that veers away down, but when Sam snaps his lighter on and holds it forwards, the flame is steady, and so they move on. There is a small pit in the ground that Sam side-steps after Dean emphatically declares, "The only way you're getting me down there is in a goddamn body-bag," and then they pass a crack in the rock and Sam's lighter flickers.

 

            Sam pauses.

 

            The crack is maybe two feet wide, narrowing at the bottom, but when Dean tilts his head-lamp to peer inside, it becomes clear that it does widen as it slopes slowly upwards.

 

            Dean says, "After you." He hoists Kurt higher, his grip tightening on Kurt's arm, and he jerks his head towards the crack in the wall. "Sam—you go first. I'll pass Kurt through after."

 

            "No, I can't—I can't," Kurt says, his voice high with panic. "I can't."

 

            Sam tucks his lighter back into the pocket of his jeans, and he squeezes through first. He twists, once inside the mouth of the tunnel, and Cas' breath snags in his throat as he watches Sam's shoulders graze and bump over the walls of the tunnel—he's going to get stuck—but then Sam wriggles and turns fully, and he reaches for Kurt.

 

            "Pass him here. I got him."

 

            Dean eases Kurt forwards, hopping and hobbling unsteadily, and he supports him awkwardly as he passes him forwards to Sam, and then Dean is moving into the tunnel after them, and Cas is left alone, alone again in the cavern with the dark pressing in around him on all sides. It is by accident—instinctual, involuntary fear—that Cas bursts out, "Dean, don't leave me here."

 

            "Hey—" Dean twists his head back, and it's not easy, with the rock pushing in on him at all sides like a tomb, but he manages to look back at Cas, and his face is washed out by the cold white light of Cas' head-lamp. He is grimy, mud-speckled, with dirt on his lower lip, and in the glare of the light, his eyes are impossibly green.

 

            Cas feels the sweltering deja vu of the cave-in, roots himself to the spot.

 

            Dean reaches a grasping, clumsy hand for Cas, and Cas grabs his wrist, fingers locking tight. "I'm not leaving you behind. Okay?" Dean says, and his voice, although rough, is earnest. "I'm not gonna leave you. You hear me? I promise."

 

            Cas nods.

 

            "You gotta follow right after me."

 

            Sam's voice comes from within the tunnel, faint and distant and echoing: "Dean? Come on, let's go."

 

            Dean's fingers skim over the inside of Cas' wrist, over his palm, as he pulls his hand away. "Right after me," he says again, and he turns his head back the right way—banging his helmet on the rock, and for a moment he's forced to duck down and wriggle in the space he is afforded to get facing forwards. He is silhouetted, then, by his own head-lamp, the white light outlining him as he shifts up, and then slowly he is lost to the dark.

 

            Cas swallows. He steps in after him.

 

            It's narrow. He tilts his shoulders to allow himself more room, and still he is dragging himself along the walls, the wetness of the rock seeping through his jacket. His helmet knocks against the wall where it slopes in closer. He takes a deep breath, and takes one small step, shuffling. The tunnel narrows at the bottom, so that he can't set his feet down straight; he has to tilt his feet at awkward, ballet angles to keep his boots from getting stuck.

 

            But—he can fit. He's fine. He can hear his own breath, laboured and loud and unsteady. Water drips from somewhere above, lands in the collar of his jacket and trickles, icy, down the length of his spine.

 

            Cas reaches out with his hands to help feel his way along. It's too small a space for him to able to use his head-lamp to see where he's going, so he fumbles with the wall, scraping his fingernails along rock and stubbing his fingers on unseen bumps and cracks. He breathes. He swallows the mounting anxiety that spreads coldly underneath his skin and he breathes.

 

            Sam's voice comes back in distant, echoing fragments. _Up just ahead._ Then Dean's voice, closer, surreal in its proximity in the total dark. "It opens up just ahead. We're nearly out."

 

            Cas sets his jaw, curls his hands into fists. He can fit just fine. There's nothing to be afraid of.

 

            He scrapes slowly forwards until, sure enough, the tunnel widens and widens, and there is room at last for the four of them to stand together. Kurt is shaking, paler than ever. He sways, balanced on one foot, and sags against Dean's shoulder—Dean, who slumps where he stands, tired.

 

            "Okay," Dean says, panting. "We gotta—switch out. I can't—"

 

            "I'm sorry," Kurt says. "I could try to—"

 

            Cas steps forwards. "I'll take him."

 

            "Thanks." Dean staggers forwards into Cas' space, hip-checking Kurt to get him closer to Cas so that there's no time for him to over-balance or fall. Dean's fingers graze over Cas' knuckles as he drapes Kurt's arm around Cas' shoulders. "You got him?"

 

            Cas nods.

 

            "Alright, let's keep going," Sam says. "We can't afford to waste anymore—"

 

            Sam is still speaking, but there is something else twisted into the sound—a whisper.

 

            Three slow, echoing, discordant notes of a melody that Cas remembers in his gut.

 

            "Quiet," Cas says abruptly.

 

            As Sam, Dean, and Kurt fall into a bewildered hush, Cas is listening—but he doesn't need to have made them silent, because the sound is not dwindling into the shadows as it has before. It's not coiling in his skull, out his ears.

 

            It continues. It grows louder.

 

            Two voices.

 

            Three.

 

            "It's them," Cas says.

 

            Dean stares at him. "What?"

 

            Four voices. Five. The voices are tumbling over each other, snaring together so that words and melody are indistinguishable—just a writhing mass of sound.

 

            Cas says, "Whatever's down here. There's more than one. They heard us."

 

            Sam asks, trying to disguise the tremor in his voice, "How many?"

 

            "I don't know." Cas' voice is tight.

 

            "Oh, God." Kurt is having trouble breathing. "Oh, God. Oh, God—"

 

            Dean's face is set, hard. "Alright. Time to go." He pulls his climbing axe out from his belt, weighs it in one hand, and he says, "Cas—lead the way. You two are gonna be slowest. Sam and me'll bring up the rear."

 

            Cas stares at him. "Dean—"

 

            "Move it!" Dean shouts, and Cas turns away, grips tight onto Kurt's waist and starts walking. With every step, Kurt winces, or bites off a sound of pain, and he is shaking so badly that sometimes his good leg buckles beneath him and nearly drags them both down.

 

            "Come on, Kurt," Cas urges. "Get up—get up!"

 

            The voices are building, building, rattling off walls, into a sibilant, rolling thunder inside his head, but he can hear now—the clicking of feet or of claws, a kind of cicada-rattling. “It's them, it's them,” Kurt is sobbing through jagged breath, and Cas tries to move faster, but Kurt is stumbling over his own feet, and then his broken ankle hits a jutting rock and he screams. His knee gives out. He goes down.

 

            "Kurt—" Cas starts, and then Dean and Sam are nearly crashing into the back of them.

 

            There is a horrible rattling shriek as Dean's knee connects with Cas' spine, so close it raises the hair on the back of Castiel's neck.

 

            "Go!" Dean yells, and he has a handful of Cas' sleeve, suddenly, yanking him up hard enough that his helmet collides with the wall of the tunnel behind him, and the glare of Dean's head-lamp is spinning in Cas' vision until everything is hot white spots and he is disoriented. "Go! Get out of here, Cas, go!"

 

            There's no time to say anything back, to get a look at the brothers' faces—Cas slings Kurt's arm around his neck, grabs a handful of his pants at the thigh, and heaves him onto his shoulder.

 

            "Hold still—hold still—"

 

            He runs, blindly into the nothingness, into the heaving, gaping tunnels that wend and wind open in front of him.

 

            They are too wide for the passageway and Kurt's ankle hits the wall with a sickening crunch, and he screams, and Cas twists to yank him through, and he keeps going. There is a skittering of rocks, dust swirling down from the head of the tunnel, and there is a blood-curdling, throatless noise from somewhere behind them, and Sam, shouting, and Dean's panicked, _Sammy? Sam!_ and Cas falters. He turns back.

 

            The white beams of the head-lamps behind him are jumping, swinging, as they move, to splinter from the narrow, black walls, and in the moving light, Cas can catch glimpses—the glinting arc of Sam's climbing axe, the smear of dark over Sam's mouth, the ragged, bone-broken, many-jointed limb that snatches and slashes, _something_ skittering across the walls and writhing in the darkness—and in a voice too small for the space and the slaughter, he says, "Dean—Sam—" and then Dean is staggering, bloody, after him, and Sam is still coming, so Cas turns and he runs.

 

            Kurt is slipping, Cas' sweaty hands are fumbling on Kurt's arm and thigh; his weight keels over heavily onto Cas' one side, and so he staggers, lopsided, and he crashes into the wall, and Kurt is shouting in his ear, "Go—fuck, keep going—" and Cas' head is spinning. He is blind in the dark, his head-lamp flashing over rock and rock and rock, everything identical and alien.

 

            The tunnel forks. Cas veers left, and then the walls narrow to press in close around him, threatening to crush him, and Cas' heart is a frantic, breathless drum beneath his ribs. He twists sideways, squeezes through with Kurt on his shoulders as best as he can, chased by Dean's voice— _keep going, keep going—_ and by Sam shouting, and by the roaring snarl of ancient, tangled voices, and Kurt's helmet hits the wall, and Cas has to put Kurt down. He has to hold him up as best he can and drag him, and then there is a short slope and his feet go out from under him and he slips and lands hard on one hip, and Kurt crashes to the ground, and then the earth beneath them is gone.

 

            Cas doesn't make a sound.

 

            He is good at falling.

 

            His breath seizes in his throat and he is swallowed by the dark, his head-lamp finding nothing to light upon, weightless and lost. Then, finally, there is the ground.

 

            Kurt lands first—badly—with a sickening snap and an agonised, echoing howl. And then Cas hits the ground, shoulder and hip down, and he tumbles into an out-of-control, inelegant roll, and then his head cracks hard against the rock.

 

* * *

 

 

            Sam can feel Dean at his back, crouched low, breathing hard.

 

            They've both frozen in the middle of the chamber—they'd burst through into it moments after Cas and Kurt vanished around a corner, and now the rattling, terrible things have followed them out, dispersed along the walls.

 

            Circling. But not attacking, yet.

 

            Perching.

 

            Around them the cavern is wide and black and all around Sam can hear them—horrible, clicking and clattering, the sounds of nails or claws or bones raking over rock.

 

            Underneath it all, a kind of singing.

 

            “We need light,” Dean whispers.

 

            “They'll see us.”

 

            “We _need light._ ”

 

            Sam swallows hard. He moves only his arm, angles it back until he finds the last flare in Dean's waistband behind him. He pulls it out.

 

            A stone clatters away from his feet and something in the vast dark screeches. Sam freezes, closes his eyes, waits for the noise of approach—but there is nothing.

 

            “Do it,” Dean hisses.

 

            Sam lights the flare and drops it to the ground beneath their feet.

 

            “Oh, fuck,” he breathes.

 

            He's never seen anything like them.

 

            There are three—maybe four. He's too afraid to turn his head.

 

            Crawling slowly and deliberately over the chamber walls, like huge white spiders. Maybe their bodies looked human once. He can't tell. Twisted spines, heaving rib-cages, limbs too long and triple-jointed and probing out like antennae—flat white faces, glistening, gaping—he can make out the deep black holes where eyes should be, the flesh around them oozing, seeping, can make out the vast black knife-slash of a mouth.

 

            “They're blind,” he whispers.

 

            They aren't reacting to the flare, at least—Sam watches them, clicking softly to each other from way back in the depths of their throats. He turns his head—Dean crouches lower.

 

            “Shit.”

 

            “What?”

 

            “One exit,” Sam whispers. “Look.”

 

            A narrow space in the wall through which Cas and Kurt disappeared, and over it, miming like a deep-sea crab over the empty hole, the biggest one of these—things—if Sam wasn't so sure it couldn't see them, it'd be looking right at them.

 

            Dean takes a hesitant step forward, lifting his pistol, thumbing the safety.

 

            “Don't,” Sam hisses, turning just enough to see him raise it, aim it at the thing above the exit. “Dean.”

 

            “I shoot it,” Dean whispers, “we run.”

 

            “Dean—”

 

            The sound of the shot in the chamber is so loud that Sam goes immediately deaf—he stumbles forward, startled out of balance, and the next thing he sees is one of the creatures hurtling towards him off the wall, its mouth stretched impossibly open in a shriek that he can't hear—he feels Dean grabbing at him, pulling him backwards toward the exit, but the thing is too fast, knocks Sam onto his back, knocks the wind out of him.

 

            He scrambles for the climbing axe that's been jolted out of his hand and flails it upward toward the thing's rotting face, hoping wildly to connect with tissue or bone—his head is full of ringing noises, and slowly the thing's scream comes through, hot and piercing like blood to his eardrum, Sam cracks it in the side of the head with the blunt end of his axe and it topples off him, wounded but not dead. It skitters away to regroup and he clambers to his feet as best he can, turns just in time to see the big one crawling rapidly down the chamber wall, hissing and clicking—Dean missed his shot—Dean's there, in the flare-light, taking aim again—

 

            Sam's chin meets the floor and he tastes blood and feels claw-like talons digging into his flesh—he spits something out, maybe a tooth, whatever is on top of him is heavy and he grabs frantically for purchase on the floor but it's dragging at him, drawing blood beneath his jacket—he kicks upward and back, feels his heel sink into something and a gibbering scream directly in his ear—he has to get up. He has to help Dean—

 

            He kicks again and the thing lets go of him and he manages to roll out of the way before it can latch onto his leg again. Grips his climbing axe in both hands—it seems to realise he's gotten away and turns blindly toward the noise of his carabiners clanging at his hip, opens its huge mouth, its jaw unhinging, and before it can let out another one of those horrifying noises Sam brings his arms down by instinct, plunges the blade of the axe into its skull, yanks it out and brings it down again, breathing in frantic sobs, over and over, until its head is a bleeding pulp on the ground and he hears another gunshot and swings his head sideways, maybe he shouts his brother's name, he doesn't know, he can't hear anything.

 

            Dean has dropped his gun and is swinging with his own axe now, and Sam half-crawls across the floor, digging at the earth with his toes, trying to propel himself up and into the fray of the two things trying to snatch at Dean's ankles, he tackles one and slams its head into the ground, puts his axe through its empty eye-socket—the room is full of his brother's shouts and the creatures screaming, there are two left, or maybe one—he can't see for the thick black blood in his eyes—

 

            “Dean!” Sam screams, hoarse—the light of the flare is dimming and he can't properly make out his brother's shape from the shapes of the creatures—and then he feels a talon dig into his leg and lashes out, sends the big one howling off him with the edge of his axe to its face. He doesn't know where the exit is. He doesn't know where Dean is—

 

            “Dean!” he screams again, and this time Dean answers, so close that Sam almost jumps out of his skin—“Let's go, let's go!” and Dean is hauling him up by his arms, pushing him towards the black space in the wall, open now, empty, the space through which Cas went—Sam propels himself desperately after Dean's shape in the dark but then—

 

            Then Dean topples sideways and Sam stumbles to his knees and the big one is on top of his brother, Dean is a mass of flailing limbs underneath—he shouts, nothing but a noise, and then something is yanking on the back of his head, a grip in his hair, pulling his helmet off, Sam yelps and falls back and feels a huge, wet, white limb curling around his chest, like a python, smells the rank breath and the rotting flesh, feels the slick hissing in his ear, he can't breathe, there are fingers digging into his flesh, piercing through his jacket, curling into his skin—

 

            Black spots are bursting at the corners of his eyes. He can barely feel the axe in his hand—barely has room to move it—desperate, he pulls it in close, angles the blade as best he can, _pushes—_

 

The noise in his ear gets louder, hotter, a whine and then a shriek and then a scream, and Sam pushes as hard as he can until he feels the blade break the thing's flesh and feels hot, tarry blood spilling out on his hand and it lets him go and he rolls to one knee, gasping, yanks the axe out and brings it down.

 

            Six times. Seven. He loses count. He doesn't know. He can't hear. The scream was so loud, so close, he doesn't stop ramming down the axe until the only sound is the huge ringing in his ears and—the noise of something moving up behind him fast—

 

            Sam pivots. Stands.

 

            His axe slams hard through Dean's throat.

 

* * *

 

            "Oh, God," Kurt groans. "Oh, fuck. I can't move. I can't move."

 

            His voice takes a slow roll across the ceiling of the cavern until it meets Cas' ears, and by then it's muffled, dripping like molasses. His eyes are still closed. His head is a firework of pain. He isn't ready to move yet.

 

            Quietly, Cas tries to take stock. Except for his head, which feels like it's rocketing around inside his helmet, he's not in any pain. He's face-down in what feels like sharp rock, but it smells like blood—it's probably bone.

 

            Cas takes a deep breath, begins the agonising process of curling his body inward, feeling intently for any pain inside him, ruptured organs, broken bones. For an instant he feels a hiss of irritation, that he even has to think about these things anymore.

 

            For an instant he catches himself wondering if his wings are broken, before he remembers.

 

            Kurt is moaning behind him, lower—he must be on an incline of some kind. He's making noises that Cas has never heard from a human throat before, and he's not too eager to find out why.

 

            He turns his head-lamp on, shocked that it still works, and slowly rolls onto his back, levers himself up with the heels of his scraped, bloodied hands.

 

            Kurt is a shadow-mass on the floor of the cavern below him. And he is resting on bones—a small hill of shards and fragments thin enough to pick teeth with, pricking into him every time he shifts his weight.

 

            Cas tilts his head, sweeps his light across the chamber.

 

            Up above to the right, his lamp vanishes—the hole they must have fallen through. Cas swallows thickly. There's only silence from up there.

 

            He thinks about calling their names. Maybe Sam and Dean overlooked the pit. They could be up there right now, wandering through the dark, looking—or else—

 

            He doesn't say anything.

 

            Cas inches his way down the bone slope on his ass, wincing, his head full of the stench of rot and blood, towards Kurt's whining, sobbing huddle on the floor. Even in the dim swinging light he can tell it's bad—he sees angles to Kurt's limbs that don't make sense, sees dark shapes pooling on the earth. He's bleeding.

 

            Cas pauses to look back up at the hole. He grimaces. There's no way to get Kurt up through it on his busted ankle. It's going to be a challenge to get himself up there alone.

 

            He stops to rest a few feet above Kurt. His head is swimming, his hands are bleeding—and there's no sound from up above, and he doesn't know what that means. He squints his eyes shut for a moment. When he opens them, chances a look across the cavern past Kurt, he pauses.

 

            There is something written on the far wall.

 

            Cas fumbles with his head-lamp, adjusting the beam, and gets to his feet—nothing broken, thankfully—staggers slowly forwards to see. For a moment, he can't comprehend it. He stares at the foreign symbols and doesn't see.

 

            Then, slowly, he realises what he is looking at: Enochian.

 

 _FATHER,_ it says, scratched roughly in bone and blood. _FATHER._ It is ragged and uneven. _FATHER._ Over and over and over. The sigils of one tangling into another. _FATHER. FATHER._ Stretching as far as Cas can see, every inch of rock covered. _FATHER._

            The melted flesh left in oozing puddles throughout the caves - from a creature shedding its skin, yes, but not willingly.

 

_FATHER. FATHER._

 

            Cas remembers dragging himself out of the dirt, the sky ablaze overhead, his skull shaking with the shrill-screaming agony of his brothers and sisters as they burned. He remembers the same thing in his mouth: _Father, please. Father._ The news reports in the days that followed—mutilated, molten corpses littering the northern hemisphere, dead on impact or shortly after.

 

            In a way, Metatron had done him a favour, stripping him of his Grace before he fell.  Nothing to ignite on the way down.

 

_FATHER._

 

            No angel survived, Cas tells himself as he steps unwillingly closer. No angel could have survived.

 

            There is a soft, distant sound behind Cas. He half-turns his head towards it. Something dully clicking, with a voice in it that rises, falls, that shushes discordantly off the cave walls and echoes faintly back.

 

            It sounds like song.

 

            Cas looks up, very, very slowly, to the hole above their heads, where the music is drifting down.

 

            Kurt's sobs begin to get louder, to quicken with his breathing.

 

            Cas takes a slow inhale, lowers himself to the floor. Exhales there, flat on his stomach, his shoulders tight. He catches a glimpse of something bone-white moving, achingly, down the cavern wall.

 

            They're coming.

 

            “Castiel,” Kurt whimpers. He's seen it too. “Get me out of here. You have to get me out of here.”

 

            But Cas doesn't answer. He's transfixed.

 

            There's only one—so far, at least—and it crawls slowly into the beam of Cas' light, its head swinging gently from side to side, like a dog scenting for game.

 

            Kurt is shaking, frozen. Cas can hear him rattling the bones beneath him. Still he doesn't move. His head is working overtime past the thunder inside it. There's no way to get Kurt out. Not past that thing. Not now. Not without getting himself killed, and brutally.

 

            Cas lies there, watching.

 

            The thing—angel, Cas thinks, with a bitterness rising in his throat, a hotness welling in his eyes— _angel_. It crawls forward over the floor, a pale, hideous thing, faceless, eyeless, its entire body clicking as its joints roll over each other—

 

            Cas has never seen an angel incarnate without its skin before. Has never dared imagine it. Has comforted himself imagining that everyone, like Anna, made trees when they fell, made meadowlands and mountains.

 

            Not like this.

 

            Kurt makes a noise. A whimper of fear. Maybe it's involuntary.

 

            It's a mistake.

 

            The angel turns its head toward him, and then it moves—much faster than before—moves toward the crumpled young man like a spider honing in on its prey, and Cas knows he should shout out, distract it, do something—

 

            But he doesn't.

 

            His lamp flickers. The first notion he has that the angel has attacked is the scream Kurt lets out, and then the sound of something rending—flesh from bone—in Kurt's scream. His lamp comes back and Cas presses himself flat to the floor, staring.

 

            “Cas! Castiel! Castiel!” Kurt is screaming, and it's coming out in warbles past the blood gurgling in his throat, and Cas sees the hulking shape of the angel already wrists-deep in Kurt's abdomen, tearing away handfuls of flesh and organ, its rolling clicks coming in short, sharp bursts from its gash of a mouth—Kurt tries to fight back with his one good arm, uselessly. There is more movement up ahead, and Kurt screams, “Castiel—help—” and Cas lies on his belly in the bones and the blood, and he doesn’t move.

 

            They set on him like ravenous dogs. Cas stays still and silent. He doesn’t breathe. His head-lamp stays trained on the carnage ahead and he does nothing.

 

            Kurt's screams have stopped, abruptly. As if a song has ended.

 

            There is only the sound of them now, panting, groaning, creaking, clicking, whispering, digging and pulling, excavating Kurt's body like archaeologists, emptying him like a tomb—and Cas watches, horrified, realises his head-lamp has gone out, and that he's seeing by _them—_ a soft blue glow emanating from their twisted, pale, horrible bodies, so soft it hurts to look at.

 

            Then—

 

            Something heavy shifts across the floor, and Cas sees Kurt's head being shoved into view, away from the mass of angels. It's limp. He's dead. And he sees—

 

            The first angel, covered in blood, smeared with it.

 

            Manoeuvring its long, long limbs, it freakish head, across the splayed gore that used to be Kurt, across the gaping maw of his pried-open ribcage.

 

            Trying to climb inside.

 

Cas thinks of the first moment of possession, of stretching and twisting Grace to fit neatly within the flesh he’d been given. Settling beneath the skin. Getting comfortable.

 

He lies frozen on the ground, watching, as the angel thrashes, screams a long, rattling noise, and Kurt’s body cracks, twists, as the angel moves inside him—unable to fit. They take turns, blood and torn meat dripping from their long, mutilated legs, from their blind, mangled faces, but eventually they give up and they slink away, clicking, singing. One climbs the walls in swift, easy paces like an insect, to disappear through a crevice in the ceiling; two disappear down the tunnel from which they originally came; another clambers into a hole in the floor; the last angel moves towards Cas.

 

He stops breathing. He holds absolutely still.

 

The angel moves lopsidedly—some of its limbs are mangled and broken, perhaps by the fall, and drag uselessly behind it; it uses the high, arching spines of its twisted wings to haul itself forwards; arms and legs hold its torso up like a spider. It moves quickly, crawling efficiently over rocks and obstacles without faltering.

 

Cas stares at it, frozen, as it clambers through the hollow before him, bones cracking beneath its weight, and then it is upon him.

 

It sets one sharp, skinless foot between his ankles. Another in the space between his elbow and his waist, bone chafing against his jacket. A wing sweeps over his head to find purchase on the ground past him, and drags the angel’s body forwards. The last, white, faintly illuminated foot lands solidly on top of his helmet, and then away.

 

Cas doesn’t move. He holds his breath and lies, alone, in the dark and the silence.

 

It is several long moments before he is certain enough in the quiet around him to lift his head and look behind him to check that the angel is gone, but there is no sign of it, nor any others. All is quiet: no sound of singing, and no sound from above, wherever Dean and Sam may be.

 

He climbs slowly to his feet. There is a dull ache in one knee, in the shoulder and hip on which he landed when he fell, but he grits his teeth and ignores it. His flashlight is gone, his helmet gone; he digs in his jacket for his cell phone, but even before he pulls it out of his pocket, he knows it’s useless. He can hear the broken plastic rattling loosely as he fishes it out, and there is not even enough light for him to see the damage, but beneath his fingers he can tell that it has been crushed beyond repair.

 

Cas stares, unseeing, at where his hand is in the dark, and for a moment, he tilts his hand as though to drop the phone and leave it behind, but he thinks better of it. He thinks of the fuzzy, out-of-focus photographs of Dean and Sam: Dean pulling faces at a county fair, scowling in early morning sunshine; Sam knee-deep in research tomes, posing against a whitewashed motel wall for a new photo I.D. This is new to him—sentimentality. It’s inconvenient. He pushes the ruined cell phone back into his jacket anyway.

 

He walks slowly, stumbling, blind, to the thing that used to be Kurt—now a hollowed, contorted mass of bone and meat. Still warm. Cas drops into a crouch and feels tentatively through what is there. The sharp jut of his spine through his throat; the clip of his helmet; a backpack strap.

 

Cas rummages for a flashlight, blind as he is now in the dark. He pulls out spare coils of rope, some snacks, a hunting knife—but no flashlight. Cas takes the knife and tucks it into his belt. He pauses, reaches out a hand to test the head-lamp of Kurt’s helmet.

 

It buzzes, flickers, but comes to life, glaring harsh white in Cas’ eyes and illuminating the open-mouthed terror of Kurt’s slack face. There is blood spilling out of his mouth, down over his chin. The thin skin below his eyes is wet—tears, maybe.

 

Cas takes the helmet.

 

When he puts it on, the headband is wet, sticky. He leaves his own helmet in the pile of bones, and he steps over Kurt in search of the way out. He has to find a way back. He has to get to Sam and Dean, to tell them what he knows.

 

He moves to the edge of the cave, tripping and stumbling over half-seen debris underfoot—rocks and bones, skulls and crevasses—until he comes to plant his hand solidly on the cave wall. He grounds himself that way, and starts to trace a slow route around the edge of the cavern. His ankle nearly turns over on the sloping side of a low rock, and his foot slides out, into a shallow puddle that splashes cold, stagnant water into his boot. He finds the Enochian wall, a mural in fear and desperation, his fingertips dipping reverently into the rough scratchings of _FATHER, FATHER,_ the uneven shards embedded into the rock that Cas does not examine too closely. Occasionally, his fingers graze over small hollows in the rock, crevices, cracks in the stone through which he saw the angels twist their mutilated bodies and climb higher, but he can’t do that. There is another way out—there must be. He focuses on the steady rasp of his breathing, on keeping himself calm. This is how he survives.

 

His hand is cold with slime from the cave wall as he walks and walks, and he lets his eyes become unfocused in the blind dark, his headlamp only picking out endless black rock, and he walks, and then his ankle turns over on the slope of a rock underfoot, and his boot lands heavily in a puddle. Water soaks through his boot into his sock. The same boot. Cas keeps walking. His fingers graze into an uneven, unnatural gouge in the stone, a clumsy curve. The letter R.

 

Cas lifts his head.

 

He stands in the dark, with his hand on the word _FATHER_ and he breathes and he doesn’t panic. He rotates his wrist, cracks his fingers. He fell through a hole in the ceiling. It is not, then, outside the realm of the possibility that there is no other way out.

 

With dread tightening slowly in his gut, Cas tilts his chin up towards the ceiling, but it is too high, and the beam of his headlamp does not reach far enough. Its light washes out yellowy into the dark.

 

Cas stretches a hand up, hopeful, desperate. His fingers twist in the emptiness, grasping at the black air. Cold water drips from the ceiling, lands on his brow and trickles down the side of his nose. His own hand, muddy and scraped raw, is caught in his headlamp’s glow, and there is nothing else.

 

He lowers his hand to his side.

 

The angels came to tear at Kurt and left again—there are other ways out.

 

Cas moves past the wall of Enochian to find roughly the place where he lay when the angels killed Kurt, and then, beyond it, the long hollow in the wall through which one of the angels had climbed. It must lead somewhere. It must lead out.

 

Cas’ throat is tight as he stares into the crack, his pulse heavy in his ears. He isn’t going to fit. His wings—Cas braces a hand on the side of the crevice, and he lifts a foot to wedge lopsidedly into the ragged lower section of the crevice. He will fit. He has no wings. Panic is thrumming beneath his ribs like an injured bird, but he twists as the angel did, reaches with fingernails scraping desperately over the rock, and he hauls himself inside.

 

The crevice opens above, a crooked and misshapen tunnel. The rock juts and dips unnaturally, carved out by centuries of running water and by cave collapse, so that already the stone digs into the bottom of Cas’ spine, and when he tries to turn to be free of it, there is rock that presses into his throat, and there is an overhang that he knocks his helmet against, and when he tries to pull his boot from the bottom of the crevice in order to climb, he finds that his boot is caught in the narrow opening.

 

Cas breathes. He tries to gently extricate his leg—he breathes—he rolls his ankle, turns his foot over—he breathes—he jerks, in growing panic, and his boot comes free and he smacks his knee hard against the wall. Pain lances sharply down to his toes and the impact shakes loose small stones above him, which skitter off the top of his helmet, and Cas lets out his breath, slow and shaky, through his teeth. “I can fit,” he says, jaw tight. “I can fit—I’m human and I can fit.”

 

He climbs.

 

There is no room for him to turn his head and make any use of his headlamp; instead, its harsh white light bounces off the wet, shining rock walls and dazzles him, so he turns it off. He climbs blindly in the dark, fumbling and groping. He twists his shoulders through narrow gaps, presses his boots tight to the wall, uses his knees and his elbows and his bloody, aching fingertips to drag himself up—sideways—up—up. He is scraped raw and shaking and exhausted, fear and panic tangled so hotly in his throat that his every breath is a shuddering rasp, when finally his hands break open air.

 

“Fuck,” he bursts out, relief clenching in his chest. “Fuck—” He drags himself out, scrambling in the dark for any purchase, kicking free of the oppression of the tunnel, and for a moment, lies flat on his stomach in the wet, rank mud, and catches his breath.

 

Now he is free of one cavern, and finds himself in another. He doesn’t know if he is climbing closer to where he left Dean and Sam, or climbing deeper into the labyrinth. All he can do is keep going.

 

He staggers up onto wobbly feet, and he moves aimlessly onwards into the stifling dark. He ducks under low-hanging rocks, squeezes through narrowing tunnels, scrambles up steep pathways with rock worn smooth underfoot by the slow trickle of underground streams. He scrapes his palms raw on the rock. He reaches a narrow gully, and—optimistically—unclips a carabiner from his belt. However, as he digs in his backpack for rope, he fumbles, drops it, and it is gone in the dark. He kneels in the dank wet of stagnant cave-water, groping blindly with both hands, stubbing his fingertips bluntly against jutting rock. He swears in every language he knows, and he curses the dark, and he buries his face in his hands, and he gives up.

 

He moves from one tunnel into the next, and he ducks his head lower, lower, until he crawls on his hands and knees. Sharp rock digs into his knees, and he grits his teeth against the dull ache of blossoming bruises, and he thinks, _forwards, forwards_ , instead of thinking about the thousand tons of rock and mud and bone looming over his head every time the rim of his helmet knocks the top of the tunnel.

 

Mercifully, at last, the tunnel opens out, and Cas breathes a sigh of relief. He clambers up onto his feet, and promptly cracks his head on the low ceiling. He ducks with a low oath, and reaches up to switch on his headlamp. The ceiling slopes lower and lower until it is less than two feet high, but Cas’ light glints off an opening at the far end. There are bones here, too—meat-stained ribcages, a broken femur—in this small cavern.

 

He moves at an unsteady crouch, then onto his hands and knees, and then ultimately onto his belly. He drags himself forwards with his elbows, and it has been a long time since he prayed in earnest, but here, with the top of his helmet scraping the rock, hauling himself through blood and meat, with two miles of black rock pressing down on his shoulders, he hopes that he is going the right way. He hopes that Dean and Sam are on the other end of this passage. He hopes they are waiting for him.

 

Gradually, the ceiling lifts, and Cas is able to move more easily. As he sets his boot down, there is a sharp crunch. Cas glances down, expecting to see bone, or the brittle shell of some subterranean insect, beneath his boot, but sees only a shallow puddle.

 

Cas lifts his eyes to look ahead.

 

There is nothing but darkness. The beam of Cas’ lamp picks out the uneven slope of the floor, reflecting a sickly yellow in the water underfoot. Cas does not move.

 

Ahead, another crunch. A slow scraping.

 

Cas moves a hand slowly back to his belt to retrieve Kurt’s knife.

 

He holds still, and finally, there is movement ahead. The stretch of one long, bone-raw limb—wing or arm, Cas can’t tell—digging into the rock, and then an angel, heaving itself brokenly forwards over the sides of the wall. This close, Cas can see it more clearly. He can see the sunken skull, the rotten hollows of empty sockets, the head faceless and bloody. The broken limb dragging uselessly behind. The twisted, raised spine, contorting through taut flesh.

 

Cas takes a deep breath. He says, “Brother?”

 

The angel’s head cocks; every vertebra clicks and cracks with the moment, a slow ripple, ribcage flexing. One of its many arms shifts, its hold on the rock moving only slightly. The sightless, empty sockets of its melted eyes are black and staring.

 

“It’s Castiel,” Cas says. He holds both hands out of in front of him in surrender, bends one knee so that he’s lower to the ground. Unthreatening. He keeps his eyes on the angel. “Brother, do you know me?”

 

Slowly, the angel crawls down the wall towards the room. Its ruined wings move like the legs of a spider to drag it forwards, bone scraping sharply over rock. Its head tilts from one side to the other, listening. A low sound reverberates in the back of its throat, something between a rattle and a discordant hum. It’s trying to speak to him.

 

“Sister?” Cas tries. “Do you know me?”

 

The angel takes another step down the wall, its long spine cracking and shifting.

 

He says, quietly, “Do you understa—”

 

The angel surges forwards, and there isn’t time for Castiel to consider his next move; he reacts instinctively.

 

He grabs the angel’s arm, twists, and there is the sick, hot snap of bone—the angel screams, long and high and rattling, and it lashes out for him, long fingers of ragged bone-stumps like claws tearing at the front of his jacket. It moves unnaturally, in ways he cannot follow, limbs twisting as though dislocated at several joints, almost folding back on itself, and it slashes at him.

 

Cas steps back, drops, leaving the angel to snatch at his backpack instead of at his chest, and he is wrenched over onto his back, but he kicks one of the angel’s legs out from under it. It falls, nearly lands on him, its hands going, sharp and blood-wet, for his eyes, and then he twists, rolls. Pain lances up through his injured knee, but he has Kurt’s hunting knife in hand and he slashes down, hard, to rend another of the angel’s limbs not quite in half. The muscle within is grey as though with rot, stretched thin and bloodless—almost brittle.

 

It looks impossibly wrong, pressed low and many-limbed, legs and arms and the ragged remains of wings all curving to the earth to haul its mangled body forwards, and scales the wall, scuttling fast, clicking deep in its throat. The limb drags uselessly behind it as it leaps.

 

It grabs Cas under the jaw, flattens him.

 

The knife goes from his hand.

 

He lands on his back, hard enough that the wind is knocked out of him and he gasps, but he throws up an arm to block the broken shards of the angel’s fingers that slice for his throat, and he can’t breathe—chest heaving—white spots popping in his vision—groping for his knife, out of reach. Instead, he wraps both hands around the angel’s narrow sliver of wrist, where it is strangling him. He tucks his legs up, plants his boots solidly on the angel’s abdomen, and forces all his weight upwards. The wrist shatters in his hand, and the sound of the angel’s agonised scream rings in his ears like a battle-cry he remembers from millennia ago. He doesn’t think about it. He braces himself, twists, rips the arm off.

 

The angel is thrown to the far side of the tunnel, hitting the rock with a crunch that sounds, to Cas’ ear, like broken bones, but the angel seems unfazed. By now, it’s probably used to its body coming apart.

 

He rolls, grabs Kurt’s knife from the tunnel floor. The angel lunges back, and Cas drives the knife hard into the creature’s chest. He heaves all his weight into it, forces the knife deeper, drags it down, as the thing jerks and jolts and spasms, and then he wrenches the knife out—the angel getting a disfigured, bone-broken hand on him as it starts to shudder and collapse—and Cas slams the knife hard through the creature’s left eye.

 

It slumps on him, heavy, and Cas shoves it away. Its head cracks hard against the rock, and Cas stands there, staring at the sprawl of it—limbs broken and mutilated, wings little more than long curves of mangled bone. Six, on this angel. Seraph. She might have been in Cas’ garrison.

 

She might have been his friend.

                                                                                                   

Chest heaving, Cas straightens his helmet’s head-lamp. He wipes his hands on his slacks. He stoops low, then, clenching the hilt of Kurt’s knife tight, and with a nauseating sound of the blade scraping against the bone, he yanks the knife out of the angel’s eye socket. He wipes the blade unceremoniously on the sleeve of his jacket, and then tucks the knife away.

 

His backpack, when he goes to retrieve it, is torn—one strap completely severed, another hanging loose, and there is a slash in the fabric, through which the contents of the bag are already beginning to spill out. He shrugs out of it, takes what he can fit into his pockets, and he moves on. He feels his way along the wall in search of the exit.

 

There is a tunnel ahead, sloping upwards. The ceiling is low, but Cas ducks down, scrambles carefully on his hands and feet. He twists an arm around to grip at the ceiling where the ground is slippery underfoot, uses that to haul himself upwards and forwards. He swivels at the waist to fit through when the shape of the tunnel is a lopsided slant and he is too wide to fit through. Narrower and narrower, the rock presses in on his shoulders, bumps against his helmet, but he adjusts. He makes himself fit. There is dirt and blood in his mouth, and he gropes in the dark with his human hands and he drags himself through the mud.

 

Gradually, the ceiling lowers and lowers until Cas can feel the rock against his back with every breath and his heart beats wildly against the stone floor, the mud seeping through his clothes, and he does not panic. He pushes his elbows out in front of him and he hauls himself forever, his boots scrabbling against the rock, and he writhes his legs, and then he is caught and he cannot move. Cas jerks forwards again, again, and each time, something at his hip clanks against the rock and does not yield, and he can’t get through. The disorienting dark closes in on Cas, cold and thick and wet, oppressive enough that nausea tightens in Cas’ throat.

 

Cas breathes. He closes his eyes. In his head, there is the gruff warmth of Dean’s voice: _you’re okay. You’re fine. Don’t freak out—just relax. Find room to move._

He remembers that he was nearly crushed alive by a mile of mountain rock, in that particular incident.

 

He opens his eyes.

 

With a deep breath that squeezes his ribcage between the ceiling and floor of the tunnel, Cas braces himself, swallowing his rising panic, and he slowly shifts backwards through the mud to try and free his hips. The pressure eases, and there is the dull ringing of metal on rock as something falls loose. Cas can’t lower his arms to investigate; at the moment, he doesn’t even care.

 

He drags himself forwards again, and this time, meets no resistance.

 

His breath punches out of his chest in one sharp burst of relief, and he crawls faster, skids and slides a little as the floor slopes, and he gets a mouthful of mud, and he keeps going. At last, he fumbles his way out into an open cavern, and he drags himself shakily onto his feet. He pats himself down, searching, and he can’t figure out what he has lost until his fingers graze over his belt and find no knife. Kurt’s knife—gone.

 

Cas turns back. He drops into a crouch and tilts his head to direct the harsh light of his head-lamp into the tunnel, but it slopes upwards and away and out of sight into darkness. He can’t see anything but the narrowing of the walls into what, moments ago, he had been so sure would be his grave. Reluctantly, he turns away, and he looks around the space in which he now stands.

 

The cavern is large, the ceiling high, and as he turns a slow circle in search of where to go next, the beam of his head-lamp finds nothing. The yellow beam reaches out into empty space, glances off no rock or water.

 

His breath comes quick, shallow. He swallows. The silence rings in his ears, and he wants desperately to call out— _hello? Is anyone there?_ —but he clenches his jaw and says nothing. The last thing that he needs is to draw attention to himself, he tells himself. Even if he can’t shake the feeling that he is climbing ever deeper, ever further from the Winchesters.

 

Cas sets his jaw, reaches a hand for the cavern wall, and feels his way around the perimeter. There is a tunnel, tall enough to walk through, on the far side. Castiel steps carefully inside, turns his shoulder as it narrows barely beyond the point at which he can fit, and the ground breaks up into jagged crevices and jutting rock. He picks his way carefully through, and then, when it opens at the end, Castiel goes to step out, and he slips as his foot keeps going and going in empty air.

 

In panic, Cas scrabbles to keep hold of the rock wall and to regain his balance, but stones are loosened by the skidding of his boots, and they fall and fall in silence. Cas fights for breath, fear spiking hotly in his throat, and he presses back against the rock, closes his eyes, tilts his chin up to drag in deep breaths.

 

He feels it again—the urge to scream for help until someone comes to find him. To sit here and wait, as Kurt did, curled on the floor and shivering, to lay the responsibility for his survival at somebody else’s feet. Put a blade in his hand, and he will come out on top—but here, a mile or more  underground in the suffocating dark, Cas is helpless. He would take death in battle any day.

 

He thinks, then, of the angels as they are now, his brothers and sisters—in endless, deathless, mutilated agony. They probably feel much the same.

 

Cas opens his eyes.

 

Adjusting his headlamp, Cas sidles carefully across to the opening of the tunnel, and he angles his head, tries to peer over the edge. He thinks he can see something reflecting back at him in the beam of his light, but it is hard to tell. He hums into the dark, low, slightly off-key. The sound of it echoes and echoes.

 

He scrabbles at the wall beside him, fingernails ripping as they scratch dully for purchase, and then he comes away with small chunks of rock. He holds them out at arm's length, lets them hesitantly fall.

 

This time, they land. They fall and fall, and plink faintly into water: maybe ten, fifteen feet. Then again, the falling rocks might have landed on an outcropping, some small and insignificant shelf over the hundred-foot drop below. Then again, they might have landed in a deep hole, the real floor of the cavern only three feet below—shallow enough that Cas could step down easily. There is no way to be sure.

 

The only way out is forwards. Cas jumps.

 

It’s not as far down as he thinks. It’s far enough to hurt.

 

He lands hard on his feet, and then on his ass, when his boots slide out from underneath him on the uneven stone, and he smacks down hard, cracking his tailbone on the rock, and then his back hits the ground and all the air is punched out of his lungs in a wheeze.

 

For several moments, Cas lies flat on his back in shallow water, shaking, unmoving. He drags in one slow, painful breath after another; he closes his eyes, but finds himself only more disoriented when he opens them again to find the same blackness as behind his eyelids, and it makes bile rise in his gut.

 

Slowly, Cas drags himself up onto hands and knees, then upright, ankle-deep in icy, stagnant water. He wipes a wet hand over his face, then there is a slow, scraping noise somewhere up ahead, and Cas freezes.

 

He drops into a crouch, his hand drifting instinctively to his belt before he remembers that Kurt’s knife is gone. He turns his head, the white beam of his head-lamp panning across the cavern. It picks out nothing moving, glints on no bone-white body of an angel making its way towards him. There are crevices in the wall, wandering tunnels, where the light is swallowed, and it is difficult to get a feel for the space with the dark pressing in on him from all sides.

 

He stays low, and he waits in the dark, and at last, after a long, echoing moment, the sound comes again—as of something dragging roughly over rock or bone. Something struggling.

 

Cas gets cautiously to his feet. He moves, careful and quiet, through the mud and the puddles of stagnant water, to follow the noise. It scrapes again, and there is something else alongside now: a low, rattling breath.

 

There is something up ahead.

 

Cas picks his way across, and gradually he can make out the silhouette. On the ground, there is a figure sprawled on their back in the mud and bone.

 

By the length of his legs, by his boots and his jacket and the tilt of his chin, Cas recognizes Dean even before the light lands on him.

 

“Dean—”

 

His name bursts from Cas’ mouth without thinking—echoes on the stone, rings and rings—and Cas is scrambling towards him, slipping in the wet and stumbling on the uneven rock. As he moves, his lamplight is shifting, unsteady, and it flashes over and away from Dean with his every step, so that Cas is able to pick out split-second details before he reaches him.

Dean’s head tipped back, his open mouth.

 

His feet dragging slowly across the rock, trying to move.

 

Blood on his hands.

 

Cas drops down heavily beside him, his knees cracking on the rock, and he says, “Dean,” again, low and urgent, but he sees now, and whatever sense of desperate relief he felt turns abruptly cold.

 

Under the harsh light of Cas’ head-lamp, Dean’s pupils dilate. He fumbles, half-blindly, for Cas, his hand curling into the front of Cas’ jacket. His fingers are slick with blood, and he takes a deep, rattling breath. He chokes on it. Blood bubbles out of the corner of his mouth.

 

The wound is a puncture straight through Dean’s throat, not like the lacerations and tearing that Cas has seen the angels put their hands to. It’s narrow. Maybe an inch or so wide.

 

An axe-wound.

 

Cas wants to ask what happened, but the scene is already playing out in his mind—Sam’s white-knuckle grip on the handle. The force behind it. The carelessness.

 

He says, “Sam.”

 

“Accident,” Dean manages, blood staining his teeth and his tongue. His voice is wet and shuddering. “Cas—”

                                                                                                                                  

 _He left you here_ , Cas wants to say. _He put an axe through your throat and he left you here._

 

Blood is spilling up out of Dean’s mouth, over his chin. It rattles in his throat like a blocked drain. The hole under his jaw bubbles, froths. In the white lamp-light, the tear-tracks through the blood and grime on Dean’s skin stand out starkly. He has been alone and afraid, down here. He has been waiting to suffocate.

 

“An accident,” Dean tries again, and his voice bubbles in his throat. “Swear—Sam didn’t—it was an accident.”

 

Cas wants to say, _He didn’t even kill you_. The backs of his eyes sting hotly, rage and grief tangled in his throat until he can’t breathe through it _. He left you here to choke._

 

Dean’s hand is shaking badly where he holds Cas’ jacket; his fingers clench and unclench on the fabric, trying to get a better grip, but his movements are jerky and uncontrolled. Cas takes one wet, blood-dark hand in his own, holds on tight.

 

“Cas, I’m—” Dean moves uselessly, the heels of his boots scraping over the ground. A harsh sound bursts out of him – somewhere between a sob and a splutter, vomiting fresh blood—and his expression crumples with fear. “Fuck—fuck, they’re gonna come back. They’re—they’ll come back, you gotta—”

 

“I’m not going to leave you,” Cas says quietly. His thumb rubs a pattern of reassurance over the back of Dean’s knuckles, and he reaches with his other hand to smooth Dean’s sweaty hair back from his forehead. “I promise. I’m not going to leave you here.”

 

Tears well up in Dean’s eyes. “I don’t wan—” His words are lost to his next slow, shuddering breath, blood gurgling in his throat, and his chest bucks, uncontrolled, as he tries to gasp through it. His mouth is moving wordlessly.

 

Cas hears it, then: the faint, discordant melody of distant music. Two voices, call and echo. No—three. Echoing in the tunnels is the staccato of sharp limbs over stone.

 

The rhythm of his thumb over Dean’s skin stutters.

 

“They—” Dean rasps, and his eyes are darting, unable to focus. “Coming b—”

 

Dread curls, icy and thick, in Cas’ stomach. He shuts his eyes, his throat thick. He breathes though his teeth. “I’m not going to leave you,” he says, and his voice cracks. Tries not to think of those long, bone-white hands pushing into Dean’s sternum, to twist and crack and rip. “I’m staying here.”

 

“No.” Dean’s head lolls like something broken as he tries to get away from Cas’ touch. His hand gropes wildly for Cas, as though to shake him, but he is uncoordinated, shaking badly. He wraps his fingers around Cas’ wrist. “No, you gotta—go, you get out, you—”

 

It isn’t supposed to happen like this. In a hole in the earth, miles underground, in the dark and the wet—Dean choking, slowly, to death on his own blood. A hole in his throat that his own brother put there. They were supposed to have more time.  “I won’t leave you,” Cas says. “Fuck, Dean—if I’m not here, they’ll—”

 

He can’t get the words out.

 

He fell from the sky for Dean. He betrayed his family and destroyed their home and let them burn up in the atmosphere on the way down, to crash to earth as charcoal or to drag themselves, bleeding and blind, into the earth to become monstrous—for Dean. Every good thing he has done in his life has been done for the sake of the Winchesters, and if he stays with Dean now, he can fight the angels off. He can keep Dean safe. He might not make it—against three angels, Graceless, without a weapon—but he can keep Dean safe for a little bit longer. If this is all the time he has, he is going to take every second he can get.

 

“Cas—” Dean says, strained, desperate.

 

“You’re not going to die fast enough,” Cas bursts out, angry. “They’ll tear you apart, Dean, and you’ll still be alive when they—”

 

He stops short, staring at Dean, who is looking at him, red-eyed and bloody and hopeless, and who already knows.

 

Dean’s fingers tighten on Cas’ wrist, but his fingers, slick and dark with blood, are slippery. “Please.”

 

Footsteps over stone—if they can be called footsteps, the sharp, near-metallic clatter of their ragged bone over rock—echo closer now. There is a rolling cicada noise, cracking and hissing, and underneath it all, that low, unsettling song.

 

There is something squeezing hotly beneath Cas’ jaw and his throat is tight and he can’t speak. He only shakes his head.

 

“Please—” Dean’s voice is a rough whisper, cracking at the edges.  “Cas—please—”

 

“Dean,” Cas says hoarsely. “Don’t ask me to do that.”

 

Tears shine redly in Dean’s eyes, spilling over his eyelashes, and he opens his mouth to speak, but gets no words out. He coughs and retches and blood pours down off his chin, and his chest jerks irregularly as he struggles to breathe. He won’t live much longer, but he’ll live long enough for the angels to reach him. To try him on for size.

 

Surreally, Cas thinks of Dean as the Michael Sword, born and bred to be the perfect vessel. He thinks they might fit. He thinks, then, of an angel climbing into his skin, pushing the mutilated, fleshless arches of their wings and mangled limbs in alongside his bones, settling within his ribcage like a parasite. Nausea churns in his gut, and Cas tries to breathe through it. “Dean,” he says, but he doesn’t say no.

 

Dean’s hand is shuddering under Cas’ touch, his fingers shaking, smearing blood across Cas’ skin.

 

“Cas, I’m not—” Dean’s words are cut off by a sick, wet rattle in his throat, and blood pulses fresh and hot from his throat. He tilts his chin up to try to breathe through it, gags, gasps. His skin is already growing cold, greying at the lips. “Buddy, I’m not gonna—make—”

 

“I know,” Cas says. He runs a careful hand through Dean’s hair. His thumb paints blood, thick and sticky, across his temple and forehead. Dean tilts, unconsciously, into the touch, pressing his cheek into Cas’ blood-wet wrist, and his eyes close. “I know,” Cas says again. He swallows. “I’m here, Dean.”

 

He can’t say no.

 

The least Dean deserves is to decide how he dies.

 

Cas moves, then, to straddle Dean, kneeling with one knee either side of Dean’s waist, and he leans over him, cups his jaw in one hand. He wipes away the tear-tracks from Dean’s cheek, from the side of his nose.

 

He touches him the way he has always wanted to. He leaves long, dark smudges of blood across his skin, and Cas pushes his face into Dean’s blood-matted hair. “I’m sorry. I’m sorry.” He breathes in the warm, comforting smell of Dean’s soap, suffocated as it is by the sweat and the blood and the damp, and he sets his jaw against the aching grief in his chest and the prickling behind his eyes. He says, “I’m sorry.”

 

Cas kisses him. First, his forehead, gentle; then, his mouth. He tastes of blood and dirt, but his mouth is warm and sweet and soft, and Castiel feels something broken and ugly hitch up sharply in his throat. He tilts his forehead against Dean’s, pulls away far enough to breathe. He takes deep breaths. He drags them in, slow and steadying, even as he can feel his hands shaking.

 

Those hands uncurl. Slowly shift up to Dean’s throat.

 

 He doesn’t say anything. He keeps his eyes closed. He breathes.

 

His fingers lock around Dean’s throat and he squeezes.

 

There is tension all through Dean’s body, and Cas can feel him trying not to resist, but unconsciously Dean’s chest jerks and hitches as he tries to breathe, and his open mouth, dark with blood, is gasping. There is muscle pulsing beneath Cas’ fingers.

 

The scuttling, rock-skittering noise of the angels’ approach is near enough now that Cas can pick apart the distinct footfall of different angels. Three of them; four.

 

Cas grits his teeth around the sound of sob smothered in his own throat, and he eases up onto his pelvis, tips all his weight forwards into his arms. He crushes Dean’s carotid arteries, crushes his windpipe.

 

Dean is spasming beneath him, now, and it’s taking too long.

 

Cas’ hands are shaking. He can’t keep up the pressure. He makes the mistake, then, of looking at Dean’s face, and all the air bursts from his lungs in one shaky gasp—Dean’s wide green eyes, the burst blood vessel under his eyelid, the greying pallor of his skin, his hands jerking in panic at his sides. Nausea spikes in Cas’ gut, and for a moment, he thinks he’s going to vomit, but he sets his jaw, pushes harder. He shifts his weight, sets a knee on Dean’s chest, but Dean’s warm green eyes are staring up at him, wide and desperate, and the angels are coming.

 

Dean has not even lost consciousness yet; it will several more minutes after that for Dean to die. It’s taking too long.

 

The angels are close enough now that their song shatters and refracts from the walls of the caverns, drumming into Cas’ skull, and he can hear their scraping limbs as they climb the walls and ceiling, and there is no time.

 

Dean is still alive, and Cas has to improvise.

 

Cas lets go of Dean’s throat. He says, one last time, “I’m sorry.” He cradles Dean’s face in his hands, thumbs sweeping over his temples.

 

Grips hard, then, fingers shifting to squeeze the sides of Dean’s head.

 

He lifts Dean’s skull and smashes it down hard against the rock.

 

The shock of it—the hard, hollow crack—jolts through Cas, and an involuntary noise rises in his throat, a retch or a sob, but he swallows it down. He grits his teeth and he doesn’t look at the lolling horror of Dean’s eyes. He doesn’t look at him at all; he shuts his eyes tight.

 

He squeezes Dean’s head hard between his two hands, and he slams the back of Dean’s skull against the ground, again, and again, with a crack, and then with a sickening, hollow crunch, and there is something thick and wet that catches on the inside of his wrist, oozes a slow, sticky trickle down. He does it again, and again, until Dean’s skull is soft and Cas’ hands are bloody and he is breathing heavy and Dean is not breathing at all.

 

Cas opens his eyes and  stares straight through what he has done. His fingers drip wetly; there is a fine dark spray all the way up his elbows; he can feel something trickle down his face; he can feel it drip from the side of his helmet.

 

Slowly, he lifts his head to see the angels, creeping, in a slow, predatory circle, near enough that he can see the harsh white glare of his head-lamp glinting off their translucent, molten skin.

 

He is still kneeling over Dean’s body. Cas climbs to his feet, unfolding to stand straight, and he stares unflinchingly back at them.

 

He lets them come.

 

They surge in towards him, and he has his blood-dark hands either side of the pinion of one’s wing, and the crunch, crack, hollow scream of it is still ringing in his ears as he moves on the next one, pushes his thumb through the charred eye socket, uses his weight to throw it to the floor and smash the skull upon the rock. Dodges the flailing of a clawed hand, shoves a fist up under the upper arm to dislocate the shoulder, snaps the elbow. Stamps a boot on the face. Again. Again.

 

Something hits him, draws blood. Pain throbs in his arm, in his jaw, but it is muted, as though seen on someone else’s body. He ducks, twists, comes up behind one—moving faster on two legs than they can manoeuvre with their many ragged limbs—to grab one wing and twist. The sound of bone breaking echoes within his skull. He wrenches at the wing, puts all his weight behind it, and with a sick popping, the wing comes off, and Cas uses the momentum, swings with it, slashes the ragged knife-end of the broken bone at the next angel, carves a deep gouge through the side of its face. He is kicked or slashed at, propelled backwards; his face hits the floor. The head-lamp of his helmet smashes, leaving him in darkness. Hauling himself back up, he presses his palms to the rock and finds glass. He moves, somehow, in the dark, and he is making a sound he cannot identify, screaming or crying or singing, and he moves, fast, violent, precise, to push a shard of glass through their throat. His hands are bloody, his mouth open, and he is alive. His heart is thunderous behind his ribcage and he rips, and he tears, and he feels again like the wrath of Heaven. With his bare hands, he breaks them.

 

Then, at last, he is still standing. His lip is split, his helmet gone. His hands are wet with blood; he feels it trickle down over his face, into his open mouth. He is still breathing.

 

For several long moments, Cas doesn’t move. He is aware, abstractly, of the need for movement. More will come. He should go—up. Out. Somewhere.

 

His hands are shaking. His skin is wet—his hands. The skin beneath his eyes, aching as though scraped raw.

 

He takes one step forwards, and bones and meat crunch beneath his boots. In the absolute dark, he cannot see what—who—he is stepping on. As he shifts his weight, something pops, wet and soft, beneath his heel. Cas blinks, startled by the sound, and his eyelashes catch, stick, before separating. He rubs at his eye with a knuckle and there is thin, tacky fluid congealing on his nose, on the ridge of his eye socket. He wipes his face with his fingertips, and he feels the cold of whatever is on his fingers as it smears onto his cheek—thicker, lumpy—and as he takes another step forwards, there is a low, sucking sound as his boot pulls free from something. It is loud in his ears, like a struggling drain, like choking. His next step staggers, and as his boot comes down, he lands on uneven terrain, and his ankle rolls over.

 

His legs buckle. His knees hit the rock hard and the pain is fierce, wrenching a small, half-strangled noise from his throat.

 

On all fours like an animal, Cas is aware, suddenly, of the sharp, hot taste of bile in his mouth, of the adrenalin that still thunders with his pulse until the beat of blood within his skull is all he can hear. His arms shake near the point of giving out beneath his weight. He is still breathing, but not right—his breath shuddering in his lungs—and his shoulders bow as he curves inwards towards himself in a jerky, convulsive movement with every rasping breath. He curls his hands into fists, ragged fingernails grating across the rock.

 

Cas closes his eyes. It’s as dark as it is with eyes open, but like this, he can believe that he is out in daylight, that he can lift his face into the sun’s warm rays and inhale the cool mountain air. He is still breathing. Still breathing.

 

He sets his jaw.

 

He opens his eyes to the darkness, lifts his face into the heavy, stagnant cold, and slowly, he straightens up and climbs to his feet. Bone splinters beneath his boots. Something drips off his chin. His hair hangs, sweaty and sticky, over his face.

 

The quiet drums in his ears with his pulse, echoes like a migraine within his skull. All he can do is keep moving.


	3. Chapter 3

The dark down here is timeless.

 

Cas is swallowed by the yawning blackness of the caves, nowhere he can go which is not dark and empty and silent. His only knowledge of the passage of time is that the blood on his hands is dry—not tacky, but dry. He can feel the crust on it beneath his broken fingernails. He can feel it stiffen the collar of his shirt.

 

He takes one staggering step, then another.

 

He is thirsty. Hungry. Pain still throbs fiercely through him, fierce enough that when he jostles his bad shoulder against a wall where the tunnel narrows, it makes his head spin. He is tiring. He doesn’t slow down, but he can feel it in the small of his back, the muscles tight and stiff. His thighs ache, and his knees must be black with bruising, and there is a blister pinching at the back of one heel.

 

Part of him wants to speak purely for the relief of a human voice, but he is vigilant for angels, and he wants to give them no excuse to come searching for him. He ducks under low-hanging rocks, squeezes through narrowing tunnels, scales a rock face that is not quite vertical but close. He keeps moving, always moving. In circles, at times. Into dead-ends and into cliffs he cannot scale and into the same three caverns before he finds the next way, through a mud-slick passage a meter above his head and half as wide, dragging himself through by his fingertips. He lands in water. He wades and he stumbles and he swims and he hauls himself out of the stagnant pond and straight into a corpse.

 

A woman, sprawled out supine, flesh cold. Cas’ hands move perfunctorily to investigate in the dark—waterproof clothing, tacky with blood; a series of dully jangling carabiners clipped at her hip; a climbing helmet.

 

Sue Harrison died the same as the others, her ribcage pried open with such force that her spine has snapped, leaving her body in a sharp arch away from the mud, her legs splayed out gracelessly. Mangled gore spilling untidily from within her open gut. Her throat, however, is torn out—at least, Cas thinks, she will have died quickly. The wound is deep, slashed cleanly through windpipe, carotid artery, spinal column; her head tilts back at an impossible angle as though there is little keeping her head on her body. She has a rock clenched in one hand, but the wrist is broken, the bird-fragile bones crushed by a grip stronger than her own. Her eyes are still open.

 

Cas has no time for sentimentality. He flips her over.

 

Ignoring the thick, wet sound of meat slopping from her split ribs, Cas gropes for a backpack, for a knife or a climbing-axe—anything useful. Her bag, however, is nowhere around. Over the crook of one elbow, she has several coil of coarse climbing rope; Cas’ fingers skim over the rough fibers and find a carefully tight knot, a large loop. He drops it and keeps searching. He doesn’t need a noose.

 

            Cas greedily unwraps a half-eaten granola bar from her pocket, shoves it into his mouth with gore-sticky fingers, chews as he lifts the corpse by a handful of Sue’s jacket and shakes her. Something cracks dully; her skull hits the rock. He finds her canteen, but the lid is off—she must have been resting when they caught her—and the water has seeped into the mud. He pours the last, stagnant dredges into his open mouth, runs his fingers around the rim of the canteen, sucks on them for whatever drops of water he can get. His mouth is still dry. He can still taste blood.

 

Up ahead, there is a scraping, shuffling sound of movement.

 

Cas stills.

 

There is a soft murmur of voices, a low melody vibrating, a chatter of clicking in response, thick clunking bursts of breath like a stalling engine. Three of them—maybe four.

 

He breathes, slow and shallow, as he listens to their approach, shards of mangled bone dragging over rock with a faint screech that sets Cas’ hair on end. There is nowhere to go. He sits back on his heels and watches and wait.

 

Before they come into sight, they make themselves known by the dim, blue luminescence of their bodies, the light emanating softly from the tunnel ahead. Then they appear, hunched, pale, horrible, half-scuttling, half-hauling their broken bodies forwards by the stumps of their flesh-peeled wings.

 

Cas holds his breath. He lets them pass. Three of the four sniff and snarl at Sue’s body briefly, pawing through her guts until their hands scrape bone and cartilage on the other side, and then move on; one clicks and hisses and crawls slowly nearer until it is less than a foot from Cas’ face. Its swollen, eyeless head tilts and sways in front of him, blind but suspicious; its mouth opens as though tasting the air. Cas stares impassively back at it, unmoving. His chest is tight, his lungs straining at the seams with the need for air. He doesn’t even blink.

 

At the water’s edge, past Sue’s body, one of the other angels left out a harsh, grating shriek that fractures against the cavern’s hard edges and echoes shrilly until it rings in Cas’ ears, and then all four angels scramble away. They scale the walls with insectoid ease, all limbs and cracking of skeletons until they disappear into crevices and gullies etched into the rock.

 

Cas exhales.

 

He eases himself onto his hands and knees, and then up onto his feet. He walks and walks, stumbling, blind, his hands outstretched, until he finds the edge of the cavern. The darkness is complete now, Cas’ helmet useless and far behind him. He lets his hand glide sightlessly along the wall in search of a crack or crevice through which he can carry on climbing; his fingers dip into spaces that he cannot see, and he tips his head slightly, hums a low note, listens to it echo.

 

He follows the fractured sound of his voice as it returns to him, hears when it rings and rings, and when it doesn’t.

 

The tunnel is tall enough for Cas to walk upright, wide enough for two people side-by-side, although the ground slopes underfoot and he finds himself walking with one shoulder to the wall. It helps; it grounds him. He walks, and he comes to a step in the rock—only two foot or so high—which he climbs, and the water from the dank stone of the tunnel wall seeps through his jacket, and he walks, and he trips over jutting rock underfoot, and the tunnel curves, and he follows it. He follows it until he sets a foot out into the darkness and feels nothing beneath his boot.

 

For a moment he wobbles wildly, clutching at the wall and trying to right himself, one arm windmilling in the dark, and he presses himself back desperately against the wall. He crouches, finds a loose stone, and holds it out over the drop. Lets it go.

 

The falling stone cracks against the floor almost instantly.

 

Cas lowers himself to sit on the edge, but before he has even lowering both legs, his boots touch the rock below. Not a ledge, but a step—only two foot or so high.

 

He stands. Stretches both arms out at his sides, pushing himself away from the wall. He takes one step right, and his hand touches the wall on the tunnel’s far-side.

 

A dead-end. He has spent the last minutes carefully picking his way down into a dead-end.

 

Cas’ arms fall. His hands hang loose at his sides, and he stares unseeing into the darkness.

 

Back to the main cavern. Back to—

           

It isn’t supposed to be like this. Creatures of light and song and glory—a mile underground, sightless, starving. Waiting to die. Grasping, hopelessly, at anything lost that strays too close, desperate to find the body that will allow them to return home. And here is Cas, stubbing his toe every thirty seconds, lurching unevenly on the uneven rock, groping blind for his next movements, playing at hopeless guesswork in terms of his escape, with no idea as to whether he is making his way out or climbing deeper into the mountain, taking wrong turns and dead-ends and fumbling to turn around to go back the way he came.

 

Frustrations bites hot in his throat and he wants, selfishly, childishly, humanly, to stop. To say, _I don’t want to do this anymore. I want to go home._

 

This isn’t the way it should be.

 

He keeps walking. There is, eventually, another way out—a crack in the near wall, as Cas feels his way back to the main cavern. The crack is twice the breadth of his shoulders, but as Castiel steps inside, it narrows and narrows, and the floor slopes upwards until it breaks again into a steep tunnel up.

 

He takes a deep breath. He will fit. He is human and he will fit.

 

He plants his boots solidly, jamming his toes into crevices, skidding over wet stone until he finds any rock jutting enough to set his weight on. He digs his fingers in, sets his jaw against the prickling that rises on his spine as his fingernails grate and squeak over rock. He climbs.

 

Cas’ elbows knock against the rock and he bangs his knee against the walls of the tunnel as he tries to manoeuvre, the tunnel veering briefly away until it is almost horizontal, and he flattens himself onto his belly to wiggle through. Stagnant water seeps through his shirt and jeans. He uses his elbows to drag himself forwards, moving at a sluggish army-crawl, until at last the tunnel curves upwards once more. Cas fits his boots into cracks in the wall, uneven lumps of stone where he can rest his weight, and he pushes himself up and up, wriggling where it is narrow and his hips get stuck, and then his shoulder hits a rock outcropping.

 

Cas stops short. He squirms in place—his knee knocks painfully against the stone wall—and he twists to fit his shoulder through the gap that he is afforded. He twists, and still when he pushes himself upwards, he cannot make himself fit. Below, his boot slips from one of the crevices that he has forced his feet into, and he crashes heavily down.

 

His chin cracks off the rock, pain lancing sharply through his jaw, blood filling his mouth as he bites his own tongue, and he finds himself wedged tightly into the space he has already clambered through, the rock biting into his hips and thighs.

 

Cas’ head is ringing. Blood spills over his teeth. He braces his hands against the walls and he breathes. He can hear his heart thundering inside his ribcage, beating hard enough that he thinks he can feel it drum against the rock to which his chest is pressed.

 

Slowly, Cas tries to turn. If he can’t keep going this way, he’ll have to go back. He plants his boots more solidly and tries to wiggle his hips free of the squeezing rock. He does not panic. He needs to ease himself up, and then change the angle, and then he can work himself out backwards—yes, even blind in the dark, even feeling his way out only with his feet.

 

Stretching up, Cas locks his elbows on the wall either side of his head, and he drags himself slowly up and up. The denim of his jeans snags on the rock, rips, and then there is the muted, distant pain of having scraped the skin from his body, but he ignores it. He adjusts, tilts a little, lowers himself back down—and he still doesn’t fit. He pushes and pushes, and he twists, but he can’t get back through the way he came, and the darkness is slowly but surely crushing him. Cas tries again. Again. He lifts himself up on trembling arms, his muscles torn and aching. He writhes against the rock, but he cannot get his hips through, and he cannot find the angle at which he wriggled through the first time. He can’t go forwards. He can’t go back. He can’t move—he can’t move. He can’t—

 

Cas’ hands are shaking. His shoulders are shaking. He tilts forwards, presses his forehead against the rock, and he breathes through his blood-stained teeth. His fingers are sticky with drying blood and there is mud in his eyes and it has been hours, now, since he ate, and he is going to die in this tunnel. Of all the ways to die, he thinks, somewhat hysterically, a hollow laugh bubbling in his throat. Of all the stupid fucking ways to die. He has faced archangels, the devil himself, Purgatory and leviathan and the wrath of heaven turning on him—and now, Castiel is trapped in a tunnel underground like a rat, and he is going to die here.

 

No—Cas opens his eyes.

 

There is, he realises, nothing left to be afraid of.

 

He has had his Grace cut from his throat, his wings hewn away, has fallen a thousand feet to land in the dirt, has looked up to see the light of his brothers and sisters blaze brighter and brighter until the sky was illuminated with something close to genocide, something wrought with his own hands. He has lived through the cacophony of their descent, and then the silence. He has led his family deeper and deeper underground until there was no way back. He has killed Dean.

 

If he was going to die underground, he may as well have died with Dean. He is not going to die here. He is going to escape. He will not wait to starve.

 

One more time, Cas braces his elbows on either wall, and he hauls himself upwards. There is again the blunt ache of rock carving away the skin of his thigh, the wet trickle of cold cave-water under his collar and down the length of his spine. He scrambles with his knees and his feet and his bleeding fingers until he finds the place where his shoulder hits the rock. He shifts then, until he finds a place where he can rest without the support of his arms, his boots wedged firmly below.

 

For a moment, Cas is still. He breathes, in and out. He tightens his hands into fists. He grits his teeth.

 

There isn’t room enough for Cas to stretch his arm out fully, the way he has seen Sam do it on the one occasion this was required of him—a burning room with a locked door and a small window. He folds his arm in at the elbow, his fist resting on his collarbone. He lifts his elbow as high as he can. He settles his left hand on the ball of his shoulder.

 

Cas breathes. He tightens his jaw.

 

He twists his arm, slams upwards with the heel of his left hand.      

 

Cas makes no sound. The crunch is echoing enough; the white-hot explosion of pain incapacitates him, and his mouth hangs silently open, eyes squeezed shut. His right arm hangs, useless, at his side, and the pain throbs in time with his pulse. Every second that passes, he thinks it will dissipate, allow him to continue, but it beats on and on, and Cas can barely breathe through it. He reaches up with one shaking hand—his left—and gropes through the narrow opening above for a hand-hold. He finds purchase, digs his nails in, and heaves himself up. His boots scrape desperately on the rock, and then his shoulder hits the rock again.

 

This time, the noise he makes is beyond his control. It reverberates through the cold, dank air, shatters on the stone and bounces back to him a hundredfold, a low, raw sound with teeth in it. There are burning white spots pulsating arrhythmically at the edges of his vision, but he doesn’t stop. He twists. He lets the narrowness of the tunnel pull mercilessly at the ball of his shoulder, but the resistance isn’t there anymore, and he drags himself through and up.

 

Now he climbs one-handed. He spits blood from his mouth and he crawls up and along, flattening himself onto his stomach when the tunnel slopes sideways, twisting past jutting rock, finding spaces to breathe and to adjust his useless arm, until finally, finally, he breaks out into an open cavern.

 

He takes deep breath, sinks down onto his knees in the muddy dark, eyes shut. He presses his tongue tight against the back of his teeth.

 

Slowly, he turns his bad arm, flipping his hand palm-up, and then starts to lift his hand in a wide arc over his head. It’s painful; the moment when the ball of his shoulder finally crunches back into its socket is worse.  A short, guttural noise rises involuntarily in his throat; he swallows it. He is going to survive.

 

On his knees, in the mud and the dark, Cas breathes, heavy and ragged, through his teeth. He climbs to his feet. He keeps going.

 

 

* * *

 

 

Up and up and up, Cas climbs, and then the ground drops away beneath him and he half-clambers, half-slides, down again into quagmire. The mud sucks thickly at his boots. He traces the outline of the cavern three times, fumbling in the dark, before he finds a new way forwards. The ledge is just above his head, low enough that he can climb up, high enough that it takes an effort and exertion which drags the air, rasping, from his lungs. It scrapes his palms raw.

 

He ducks his head shy of the low ceiling, and he gropes in the dark to follow the path from which the angels had appeared—a tunnel with only a few inches of space left above the crown of Castiel’s head, the floor slick with mud and sloping unevenly as he clambers inside. It opens up later, tall enough for him to walk straight, wide enough that outstretched arms only graze fingertips over the rock. It makes Cas feel untethered; he keeps his hand close enough to the wall that the ragged ends of his fingernails scratch and squeak over the stone.

 

As he staggers and climbs through the wending labyrinth of the caves, he finds something underfoot. His boot rolls over onto one side, sending him stumbling in the dark. When he throws a hand out to brace himself against the fall, he lands on something solid, smoothly furred, something that crunches under the heel of his palm and yields.

 

Two fingers touch the fold of an ear; the edge of his thumb finds something soft, clammy, like a peeled egg. His thumb-nail bumps the eyelid, and Cas pulls his hand back.

 

The animal was already dead—neck broken, judging from the angle of the head—but Cas’ fingertips are tingling with the first warm thing that he has touched in hours. He runs his hand down the long neck of what must be a deer, then down over the shoulder, and finds where it has been wrenched open, sternum to pelvis. It’s cooling fast, but fresh. Meat still soft, on the bone and where it spills out onto the rock, organ and muscle and torn skin. Not yet ossifying, not yet thickening the air with the smell of rot.

 

Cas takes hold of the deer’s two hind legs, hauls it up partway into the air. It’s heavy, too heavy to drag comfortably for long, which lends credence to his theory: there is another entrance to the cave system somewhere nearby. He lets it go gracelessly, its spine cracking dully against the rock. He becomes still. He listens.

 

Up ahead, silence. Silence at his back. Somewhere, there is the faint drip of water onto stone.

 

Cas hums, low and deep, his head canted over to one side, listens to it echo and echo. He follows the sound of it, stepping over the carcass. He’s close.

 

The possibility of escape makes him bold; he moves swiftly in search of the next way forwards. Hand gliding over the dank rock, he finds the next tunnel—wide enough that he can only just touch the other side with arms stretched, tall enough to walk upright—and as he walks, he hums.

 

He feels the space around him. The darkness about him is absolute, but it has been this way for hours, and Cas no longer feels it as oppressive, a threatening thing. He wades through the emptiness as through water, feeling it part to let him through, then press again at his heels and his back.

 

Sight is half-forgotten; he thinks if he saw his hands now, he might not recognize them.

 

There is no way to tell the passage of time. Cas’ only awareness of the passing of minutes, and then later, of hours, is of his muscles growing weary to the point of tremors. He has to brace a hand against the cold, slimy wall of one cavern to regain his breath and wait for his knees to stop trembling; in one narrow, upwards-sloping tunnel, the strength gives out in his upper arms and he slips, slides inelegantly back down on his belly, scrapes all the skin raw from one ankle and from the underside of his jaw. He walks when he can, and he crawls when he can’t, and he claws his way up through the earth and the rock in search of sunlight, like an insect, with dirt in his mouth and blood in his teeth.

 

The slow drip of water onto rock beats a slow rhythm that echoes dully within his skull. His boots scrape against the stone, and the sound seems all at once to be impossibly loud and swallowed by the suffocating silence that settles thickly around him like fog.

 

The tunnel breaks. Cas drops into a crouch, his hands on the rock: one slopes upwards, one remains level. He clicks his tongue distractedly against his teeth as he considers, fingers dragging slow over the stone, and when he decides—the level path, to his right—he moves, for a moment, still crouched, legs folded. There is a dip in the ground, a black and cavernous hole underfoot, that is easier to cross like this. He crawls over, straightens only when he has to. He clicks against his teeth and he listens to the way the sound fractures against the rock.

 

Then, ahead: a rattling scrape up ahead of bones over rock. A low, discordant song. It stands between him and escape.

 

Cas hunches himself over, moves quick and low. He braces his hand first on the wall to push himself forwards, and then on the swell of rock underfoot that needs vaulting, and when the ceiling dips it is, for a moment, easier to simply crawl, and then he is out in the open and there, ahead, is the eerie moon-blue light of an angel’s skin.

 

It lifts its head, opens its mouth in a throatless, shuddering screech as it lunges, but Cas is there already, hand around its throat. His fingers curl into its windpipe, dig in deep. With one foot, he sweeps on the angel’s many, skittering limbs out from beneath it, and in the same motion, he closes his fist and he tears. The angel goes down hard, crashes on the rock, and its blood is hot across Cas’ face as it writhes and makes its wet, gurgling scream, and Cas stamps hard on its chest. Twice—to be certain.

 

The angel gasps, dies, its limbs jerking over its mangled body like the curling legs of a dead cockroach. Cas’ boot has shattered the ribcage, the rubber heel snug in the rotten cavity of its chest. There is blood in his mouth.

 

Cas yanks his boot free and keeps moving. He ducks through the next low tunnel, moves for a moment on his hands and feet to press through the low space, uses a hand on the ceiling to haul himself forwards—easier than way—and a boot against the wall—faster than way—and then up again in search of the open air.

 

He moves with the darkness now, rather than fighting against it. He hums into the hollows of the rock to find the way through; creeps and crawls like an insect over the jutting rocks and the sloping floor and the places where the tunnel closes in on him. The ceiling drops lower and lower until Castiel slides on his belly, writhes his way through; he lets his bad arm drag behind him, alongside his hip, pulls himself along by his fingernails and then twists out into the open space on the other side. He swivels at the hips, his spine uncorking in a series of slow pops as he eases himself out.

 

He lowers himself to the ground in a crouch, his knees cracking. He listens to the dark. He can feel it breathing around him, the cold, black air unmoving. He can feel it close around him and hold him still, like keeping a cherry-pit in your mouth to scrape the flesh from stone. He tips his head slowly over to one side. Far away, there is the murmur of song. Too far to worry about. Closer, however—a clink. Cas’ mouth is open, tasting the air. He inhales the echo, lets the sound sit lightly on his tongue. He doesn’t move.

 

 _Clink_ , again. Something metallic.

 

The angels don’t use weapons or man-made tools.

 

It’s a far-off noise, half-swallowed by the dark and by the slow drip of water from stalactites and into mud-thick puddles. It is near enough, however, to be followed.

 

Cas rises.

 

He follows.

 

It isn’t easy. The noise shatters on the rock, far ahead, and echoes in fragment in every tunnel and crevice and hole for a half-mile. The path ahead of Cas forks and splits, and the sound comes from every direction, sings dully from the crack over his head and the ledge to the darkness below. He moves, slow and steady, in pursuit.

           

His breath rushes in his ears like bad radio static. His pulse thrums sweetly in his throat. There is a tic in one eyelid, the muscle jittering from the strain of trying to see in the dark; he moves better, now, with eyes closed.

 

He hums and he clicks and he crawls and he holds himself still, near-flat to the rock, as he listens— _clink_ , up ahead. One minute, two, then— _clink_.

 

The sound is clearer now: not a scraping, scuttling, broken-bone movement alongside it, as of angels, but footsteps. Someone limping. Cas follows, ducking underneath a low outcropping, moving swiftly over a boulder that juts from the floor, on hands and feet for a moment, one knee in the mud and one boot braced against the wall.

 

He presses faster through narrow gaps, slides quick through the crevice that presses in on his hips and thighs and shoulders, breathes through his teeth. He feels no fear. Up ahead, metal on rock. Ragged breath. Someone living.

 

Cas strides faster. He ducks his head low, and his hand stretches at his side—not a fist, but closer to a claw, something curled and angry, ready to snatch and tear. He is not running anymore.

 

Cas rounds the corner, and Sam hears him coming, jumps, spins—and, instinctively, lifts his climbing-axe.

 

Sam recoils when the harsh white light of his headlamp washes over Cas, his mouth falling open. His breath shudders from his lungs, ragged and shaky.

 

Cas’ eyes flick to the raised axe.

 

It is darkly stained, and it is wielded here in clumsy, panicked defense. His eyes move slowly back to Sam.

 

He expected to feel something. Relief, or maybe anger. The faint heat of Sam's body feels like a furnace in this space. Otherwise, he feels nothing.

 

“Cas,” Sam bursts out, and he lowers the axe. “Oh my God. Cas—”

 

He looks Cas up and down, and his face furrows into confusion, horror. Cas can feel what he imagines Sam is seeing now—the mud and blood with which he is stained, head to toe.

 

The brain matter.

 

“What happened to you?”

 

“Where’s Dean?” Cas asks. His voice comes out flat.

 

Sam’s throat works. “He—he’s—” His voice cracks. His eyes are red-rimmed, darting away. He swallows. “He’s gone.”

 

Cas doesn’t move. Doesn’t blink. “Where?”

 

Sam is shivering; Cas can see it in the wavering, juddering light of his headlamp, which rolls and sways with his unsteady shoulders. Sam’s mouth moves soundlessly, the words trapped behind his teeth.

 

“Cas,” Sam manages, his voice hoarse. “He’s just—gone.”

 

It’s not a confession. It’s not anything.

 

Cas says, “We should keep moving.”

 

He turns and he walks.

 

This tunnel is wide enough for both of them; Sam moves to catch up, and falls into step beside him. Cas tilts his head away, his eyes aching in the harsh light afforded by Sam’s helmet after so many hours in the dark. He glides his hand along the rock at his side, clicks his tongue against his teeth.

 

“This way,” he says, and he veers away left. “We’re close.”

 

At his side, Sam’s head is bowed, his chin tucked to his chest; he lifts his head now, his eyes wide. “You—are you serious? How do you know?”

 

“Found a fresh kill.” Up ahead, the tunnel narrows. Cas steps back to let Sam through first; his eyes follow Sam’s movements, his narrow, sloping silhouette in the black mouth of the tunnel. Cas says, “Still warm.”

 

Sam isn’t accustomed to the cave, still; he stumbles over uneven stone, gropes half-blind at the walls to guide himself forwards, swings his head wildly left and right like a panicked horse in blinders to allow the beam of his headlamp to pick out the route ahead. Cas moves behind him like a shadow.

 

“How far back is it,” Cas asks, his voice low and breaking on the rock, “to Dean?”

 

Sam stops walking. His hand gropes sightlessly towards the wall as though to brace himself; he comes up empty-handed, and his fingers curl into a fist at his side. The white light picks out the sharp crests of his knuckles, sharp like teeth.

 

“You said he was missing,” Cas says.

 

Sam’s head half-turns. “Gone,” he says. Sam’s voice is scraped raw and agonised. He sounds as though he has been hollowed by some rusty, broken thing; his breath shudders from his throat. “I said gone.”

 

Cas watches him evenly. He says, “My mistake.”

 

Silence closes around them, smothering. They walk on, but Sam keeps turning his head, his mouth half-open as though to speak; he never makes it all the way there, aborting the thought before completion. He turns to face the front, ducks under a low outcropping of rock.

 

They walk, and they climb, and they scramble through low tunnels, their boots scraping on the rock, and as they move, steady and sure, through the dark, Cas becomes aware of the distant whisper of voices. Two—three—four.

 

Somewhere beyond the beam of Sam’s headlamp, water drips, slow and steady. It rings dully against the rock.

 

At last, Sam clears his throat. He says, “Kurt—”

 

“Didn’t make it.”

 

Cas’ voice is soft, barely echoes in the hard spaces of the tunnel.

 

Sam’s jaw tightens. He gives a short nod. His eyes are shadowed by the cold white light of his headlamp on his brow, but Cas can read the tension in his shoulders, the loose, defeated look of his hands. After another long moment, Sam says, tentatively, “Did he—”

 

“We should move quickly,” Cas says.

 

Contrary to instructions, Sam stops moving. He looks at Cas over his shoulder, his mouth slackly open. “They’re coming,” Sam says.

 

Curiously, Sam believes him now. There is no trace of his polite skepticism now, his delicate, diplomatic avoidance of the issue, his hopeful justifications for Cas’ evident insanity. It is only regrettable that it took all this to reach this point—hours in the dark, blood on their hands, a hole in Dean’s throat.

 

Cas says, “Yes.”

 

Sam reels back a little, rubs a hand over the side of his neck. Cas watches the uneven lines of blood and dirt Sam that leaves on his skin. “Cas,” Sam says, voice thick. “We can’t outrun them. It’s too dark down here—it’s not gonna be easy to find this exit, and they’re too fast, we won’t be able to—”

 

“We don’t need to outrun them,” Cas says. He notes Sam’s mention of the dark with detached interest—as though the dark is a thing to be feared. He watches the unsteady bobbing dance of Sam’s headlamp, the harsh white beam swinging as Sam’s head moves. He tilts his head over to one side. “We just need to be somewhere we can defend.”

 

Sam nods. “Okay.” His certainty gives Sam courage; Cas watches him straighten, take deeps breaths. On the handle of the blood-dark climbing axe, Sam’s fingers shift and grip decisively. The light of Sam’s headlamp catches on the crusted metal, picks out the dried gore, misshapen along the axe’s ridged edge. Sam says, “Where?”

 

“This way.” Cas steps past Sam in the tunnel and he leads the way.

 

“Do you want the headlamp?” Sam asks, as he watches Cas takes slow, studying steps forwards into the dark.

 

Cas tilts his head over. Clicks, hums, and finds the way ahead a soundless path. “No,” he says, and he walks.

 

Behind them—or above them—it’s hard to say—the far-off chatter of alien, unknowable voices is nearer now. There are more of them. Cas can hear at least six, and then he is lost to the confusion of the song tangling over and over itself. It could be echoes; it could be twenty.

 

Ahead, the darkness is thick and absolute, only occasionally fractured by Sam’s lamp; he keeps the beam trained low, to check the ground underfoot and keep them from falling down any holes or from breaking their ankles in any unseen crevice in the rock. Cas glides his hand over the cold, wet stone at the wall of the tunnel, clucks his tongue against his teeth, veers them left into a new passageway.

 

It’s low, narrow enough at one point that they walk single-file, tilt their shoulders to squeeze through, narrower still at another point, so that they turn their boots sideways and tread on awkward, shuffling tip-toe through the knife-edge space at the base of the cave. It makes them move slowly, and Sam becomes jerky, volatile, with panic, his hands grabbing desperately at the walls to haul himself along faster. He crowds close to Cas’ shoulder, silently urging him to hurry.

 

It comes and goes, the rock-skitter, bone-clatter sound of them moving over distant stone and mud. One moment, the noise of their approach is far-off, muted—then gone entirely—then, echoing, abruptly, around and around them with renewed vigor.

 

Sam’s hand flexes on the climbing-axe as they move. “Cas,” he says. “Do you have a weapon?”

 

Cas has been a weapon of heaven longer than this land has had a name. His hands, however, are empty.

 

He says, “I don’t need one.”

 

The tunnel opens at last into a wider space—perhaps narrower than two arm-spans, the roof of the tunnel high and ragged-edged, the floor as even as could be hoped for.

 

Cas stares the length of the tunnel into the darkness ahead, and says, “Here.” His hair hangs, dank and heavy and matted, over his face. There is the pulse of pain in Cas’ bad shoulder, needle-sharp as it moves down through his elbow to his little finger.

 

“Here?” Sam swings around, his headlamp tracing in wide, jolting arcs over the walls, floor, ceiling, of the space around them. “There’s not a whole lot of room here.”

 

It comes, the low, throaty song, a discordant, ancient cacophony of ragged voices. Cas can’t say how many—six, seven. More. He can’t understand their speech, but it climbs under his skin, their clicking, chattering, screeching melody curling coldly in the core of him. Closer, now. Closer. It comes ringing out of the suffocating dark, tangles around Sam and Cas and holds them fast.

 

“We can’t go much further now,” Cas says, “or we won’t be able to go back for Dean.”

 

Sam makes a sound in his throat that Cas can’t quite place—the closest approximation for it that Cas can recall is the last rasping rush of air when he has pushed an angel blade through the spine, into the lungs. He bends at the waist, almost curling in on himself, and his hands scrub over his face, rake over the side of his neck.

 

“We’re not going back for Dean,” he bursts out, and he straightens up. What little that Cas can see of his expression is a contorted, ugly thing. “We’re not going back for him. We’re getting out of here. We’re not gonna die down here, we’re gonna keep moving until we get out. We’re not—we _can’t_ go back for Dean.”

 

Sam stalks around Cas in an uneven circle, spiraling. Cas half-turns his head to follow him, then loses him behind his back. Cas can hear Sam breathing, the sound as though the air is being crushed from his body.

 

Beyond them, it comes—the juddering, flayed scream of the angels, the bone-scraping screech of their broken limbs and shattered wings over the rock. They are almost upon them.

 

Sam’s head bows. His hand on his hip is vice-tight. He curls in on himself, breathing hard. His shoulders shake. The beam of his headlamp refracts on the hard, wet rock, glitters darkly in puddles, and the blackness presses in around them once more.

 

Cas stoops, drags his fingers carefully across the ground until he finds a loose rock, something wet and sharp. He fits it to his palm, stretches his other hand at his side.

 

From holes in the ceiling, from cracks in the wall, from the tunnel ahead and the tunnel behind, the angels come. They crawl and seep and scuttle, their long, mutilated wing stumps dragging over the rock. Like spiders, many-limbed, black-eyed, twisting, they creep from the walls, pick their way slowly closer. Their bones click and crack against the stone. Their breath rattles in their throats like a blocked drain.

 

Cas shifts his weight where he crouches, his eyes tracking the slow, predatory movement of the angels above and around them.

 

One crawls over the tunnel roof, its large head twisting, searching. It is sightless, its eyes long since destroyed, but something thick and black drips from the eye socket, lands on Cas’ face to trail a long, slimy track past the corner of his mouth.

 

In Cas’ peripheral vision, he sees Sam breathe dee and straighten. He lifts the climbing-axe and wields it high, defensive.

 

Cas moves. He surges forwards and he attacks, and he hears Sam’s strangled yell go up behind him, and Cas rushes the nearest of the angels just as another throws itself from the near wall towards him. With the rock in his fist, he slashes at a face, smashes it down again and again until the empty eye socket shatters and the jaw comes loose, and then the second creature lands heavy on his back, buckling his knees beneath its weight, and the agony of Cas’ dislocated shoulder sparks hotter and fierce until there are burning white spots at the edges of his vision.

 

The angel on his back hooks bone-sharp fingers into his collarbone and tears, and Cas throws himself backwards, catches the angel off-guard as he cracks it back hard against the wall of the tunnel, lands an elbow hard into its gut. He twists, gets back onto his feet, ducks the slashing of the first angel, then wheels to find a third coming up behind him—locks his hands either side of an elbow joint, and pushes the wrong way. The wing breaks. A hollow, echoing scream rises, cut off by Cas’ hand at their throat. Twists his weight to throw it to the floor, and it crashes hard against the stone, belly-down, and Cas brings his boot down hard on the base of its spine.

 

Behind him, he can hear Sam’s violence—his shouting, the grunt as he swings and swings his climbing-axe—and in the wheeling flash of Sam’s head-lamp, Cas can make out the hot, dark spray of blood, the shrieking, black-eyed faces of Castiel’s brothers as they leap and snarl and snatch, the glinting arc overhead of Sam’s axe as he slashes and hacks. But Cas spares him only a glance, because there are angels climbing like white-limbed insects, seething and swarming over the rock towards him, and he is close to being surrounded.

 

There are too many—too fast. Cas whirls to face the next angel, but as he turns, something gets claws hooked under Cas’ jaw, and then one side of his face bursts into sharp, hot pain as it yanks at him, rakes claws through his jaw and cheek, but before it can find purchase in the soft give of his eyeball, he kicks out one of many legs, kicks again and again at a knee-cap, and then he twists out of reach of a grasping, skeletal hand. He lunges, snatches, grabs—wrenches at the brittle joint of an elbow until the sound of bone splintering sings in his ears—and he is struck in the face, spitting blood, and as he reels back something snags his arms in the dark—his bad arm, jerking sharply on the shoulder that was dislocated only hours ago, and Cas makes a noise he cannot understand, and there are bone fingers tearing at the front of his jacket.

 

Cas claws at a face, shoving the heel of his hand hard against the nose, and then he smashes his hand down hard again, again, until the skull shatters. He is breathing through his teeth, and he weaves and ducks and tears, and then the beam of Sam’s headlamp turns as Sam moves—with a scream in his throat, a panicked, desperate noise as Sam slashes in frenzy with his climbing-axe—and Cas is blinded.

 

He is thrown backwards. His head cracks against the rock, and then the angel lands on him, straddles his chest, and he is pinned to the wet stone.

It rips at his chest, digs fingers into the front of his jacket and tears, and Cas kicks, struggles. He grips the wrists tight, tries to push them away or to crush the brittle bone, and something cracks beneath his fingers but does not give the angel pause, and so he reaches up with two hands for its throat—locks one hand around the base of the skull, the other pushed up tight underneath the jaw—and with all his strength, he twists.

 

The angel’s neck snaps beneath his fingers, and Cas goes on twisting, jerks the head backwards until the spinal column is completely severed, the body flopping uselessly as arms and legs and wings collapse, and then, finally, Cas throws the corpse aside, but there are more angels still, and Cas cannot roll back to his feet fast enough.

 

They are upon him—two of them—three—and Cas cannot move to get away from them. He digs the heels of his boots into the dirt, scrambles wildly backwards away from the snatching claw, the wing that slams down to punch the rock, close enough to his head that there is a sharp flash of pain and the wet heat of blood, his ear ripped ragged, and their white, flesh-scraped, eyeless heads loom in closer as though scenting him.

 

“Cas!” Sam shouts, and Cas cannot find him as he swings his head wildly, searching, but there is the metallic clatter of something sliding fast across the rock towards him.

 

The climbing-axe. Cas looks over to find it a little higher than his head—halted by the uneven slope of the floor, a jutting stone no more than an inch high snagging the handle and holding it still. It is not within arm's reach.

 

Cas throws an arm up to block the snatching of one bone-talon hand as it grabs for the front of his jacket, tries to fend off the ragged fingernails like claws that slash, hungrily, desperately, towards his sternum, and with his other arm, he stretches. His fingertips bump over metal without purchase; his blood-slick fingers fumble and fail.

 

Four angels upon him now, squabbling and scrambling over him, all hands and curving, skinless wings that slam against the rock as they fight and grasp and scream, and Cas kicks out, struggles away—his jacket and shirt riding up, skin scraped raw and bloody against the rock—and he stretches. Grabs. Snatches it up.

 

He smashes the axe hard through the top of the skull.

 

Shatters the first angel’s face from the inside.

 

It lives just long enough to let loose a piercing, rattling scream, blood and gore spilling from its open mouth onto Cas’ face.

 

He braces a boot against its slackening body, wrenches the axe out—bringing another wet, dark cascade with it as the skull breaks—and lashes out again. Slams it through the second angel’s gaping, cavernous black eye socket. He swings, uses the momentum to roll over and onto his knees, ducks the grasping thrash of another, slams the axe into the ribcage. He uses all his weight, yanks the axe back out, slams it home again. He is on his feet. He whirls, catches the next through the eye socket—turns the axe over in his hand to move fast and split the skull. Shatters a shoulder, hacks at wing and arm and throat, and a wild noise is rising in his lungs.

 

He feels, again, like wrath and lightning. Angel blade in his hand, the glory of heaven at his back, light and terror and fury, he hacks, tears, rends asunder, and he is breathless, breathing raw. Slashes open the front of a throat, slams the metal through the side of their head hard enough that the skull collapses, his boot on a ribcage to stamp and stamp and stamp and it is with his boot still buried in the bone that the next angel comes screaming towards him, all broken wings and desperate blind rage. He is merciless.

 

He can hear himself making a sound he has not heard before even on the battlefields of old, blood in his teeth and his fingers itching for retribution as they would, before, when he had the means to obliterate everyone in this tunnel by merely lifting his hand—but this is cleaner. He slashes, slices, and this, here, is all there is—meat, and the carving of. This creature, frightened, cowering, its limbs naked and broken, bone jutting yellowly from the thin, putrid flesh as it tries to drag itself away backwards to safety, and he brings the axe down to smash through the face, shatters the black-rot eye socket, and he slams the axe down again. Again. He breathes through his teeth. Again.

 

It is done.

 

Standing over the last corpse, a slow drip of thick, rank blood from the teeth of the axe.

 

A dull jellyfish pulse of pain through his side, the flesh raw and broken. His jacket, sodden with blood. His own, perhaps. Theirs. Blood is blood.

 

Sam says, “Jesus.”

 

Slowly, Cas turns his head to find Sam.

 

Some ten feet away, Sam stands, breathing heavily. The white of his headlamp washes over Cas, picks out the tangle of bodies at his feet. His voice is not quite certain—a wobbling thing. His hands shake, clenching and unclenching, empty. In the darkness, beneath the harsh spotlight of his lamp, his face is hidden.

 

A long, hard silence rings against the rock.

 

Sam says, “We should go.”

 

Cas’ grip shifts on the handle of the climbing-axe. He turns in a slow, assessing circle, his eyes moving over the massacre sprawled about his boots. Cast half in darkness by the incomplete light of Sam’s lamp, it is hard to pick out the details. Bone. Blood. Grasping hands that reach up into the air. A scattering of teeth.

 

Cas hums. He walks, slow, meditative, through the slaughter. Bone crunches under his boots.

 

When he moves, he feels the pain in his side more acutely, but it is inconsequential. They are nearly out. The exit is not far now. Here, they took out—Cas counts the bodies—eleven. Twelve. He weighs the climbing-axe in his hand. Already, he can hear the tell-tale whisper of urgent movement, spurred into action by the cacophony of the fight. In ten, perhaps fifteen, minutes, they will again be swarmed.

 

Sam clears his throat. “Cas?” he says. There is an edge of something in his words—worry. He steps, haltingly, nearer. “We need to go. More will come, and more, and we can’t fight them all off.”

 

Correct.

 

Cas lifts his eyes to watch Sam.

 

Sam is still talking. The cold, white beam of his headlamp is split by the drip of water from the roof of the cave. The darkness touches his shoulders, closes around his hands as he speaks, gesturing simply. His mouth opens, closes.

 

“We can’t go without Dean,” Cas says.

 

Sam is breathing irregularly, fast and shallow. His eyes are red and agonised, and he stares at Cas without moving.

 

“He could be in trouble,” Cas says.

 

Sam’s hand hang loose and limp at his sides. There is an uneven tremor through his fingers.

 

“He could be hurt,” Cas says.

 

“Dean’s dead.”

 

Cas looks at him. He says nothing.

 

“It was an accident, Cas.”

 

Cas watches the fractured silhouette of Sam in the dark, the tremulous shift of the headlamp’s beam before Sam lifts his head to stare at Cas; the light glares white and blinding in Cas’ face. He stares evenly into the ferocious, searing white of Sam’s light, all of Sam’s features washed out and lost to the glare of it. It is not like the white-hot glory of Grace, the air-wavering intensity of sweltering afternoon sunlight. It is cold.

 

Cas says, “What was an accident?”

 

Like a low hum of white noise, Cas can hear them come again—the swarm, like locusts, numerous beyond counting, the metallic, strident chattering of their broken-bone limbs and scuttling all twisted into indecipherable noise. They are singing.

 

Sam swallows thickly. “He was just right there—and it happened so fast—”

 

He is shaking.

 

“There were just so many of them and I didn’t think we were gonna make it, so when I heard something behind me, I just—I just panicked, and when I turned around, I didn’t think—it was an accident, but—”

 

Cas steps forward. His boot finds bone, splinters it underfoot. He says again, quietly, “What was an accident?”

 

Sam is silent for a long, aching moment.

 

Underneath his silence, Cas can hear the threat of the angels coming. Their throatless screaming comes now at a pitch that Sam can hear; he flinches. The light wavers, unsteady, trembling.

 

Sam’s voice, when he finally says it, is hoarse, far-off and lost—the first time, Cas supposes, that he has admitted, even to himself, what happened. “Cas, I—I killed him.”

 

Cas says, “You didn’t kill him.”  He says, “I had to do that.”

 

For a moment, Sam doesn’t understand—that much is apparent. He stares at Cas. He says nothing. His face is cast in shadow by the white glare of his headlamp; he is a frozen silhouette, unmoving. Cas can see the edge of his jaw, the way his throat moves. He can see nothing of the slow, unfolding realization in his expression.

 

Again, Sam says, “Cas.”

 

Cas swings the axe. Slams it through Sam’s left kneecap. The sound of it is a dull, crunching thud, and the sound Sam makes is inhuman. He crumples to the ground—climbing axe still handle-deep in his knee—and curls against the dirt.

 

He screams and he screams.

 

Cas walks away.

 

It isn’t far now. He can almost taste daylight.

 

He walks, and as he moves, he thinks, with detachment, that the voices of the oncoming hoard of angels are less urgent now. He climbs and he crawls and he thinks of clean air, dry soil, the open sky. Sunlight. His heartbeat throbs his ears and his breath rasps dryly from his open mouth.

 

The tunnels flatten and narrow and tilt, and everything narrows to sound.

 

He clicks his tongue in constant rhythm against the roof of his mouth. His breath underneath, a wash of static. Angels, now nearby, now far away, now nowhere to be heard, their strangled noises weaving in and out through every tunnel he passes, up from crevasses he moves over. The sound of his hand against the stone, against the water on the stone, and the sound of the cave, seeming to heave and breathe around him, with him. Huge, alive. He imagines he can see in the dark now, can trace the faint outlines of the walls and the rocks underfoot, although his perception of it is unsteady, judders at the edges like bad signal. He comes to a low outcropping of rock, waist-high, and when he plants his hands upon the edge to lift himself up, he struggles for a moment to lock his arms at the elbows. He is shaking.

 

Cas drags himself up and he staggers back onto his feet and he keeps moving. He breathes ragged, his throat raw and rough with dehydration, and gradually, he becomes aware of what he could not allow himself to notice, before—the fierce pain in his bad shoulder that pulses, slow and heavy and cloying, to make his head heavy; the bruises on his legs and arms and hips that make every step hurt. The aching of the muscles in his arms and thighs, the stiffness in his shoulders and spine where he has been stooped low to fit through the tunnels, the hunger pangs curling in his gut: it all crushes in on him now. There is no time to slow down. The angels have been delayed, distracted, but they will soon tire of their toy of a new corpse and will move on. They will come after him.

 

Then, up ahead—at first he thinks it's the glow of an angel, phosphorescent, ricocheting off the walls of the tunnel. He pauses, crouches, flexes and squeezes his fingers into fists. He fixes his eyes on it and creeps forward, his every nerve alert, standing up on end like soldiers at attention. His heart is pounding in his throat.

 

            It doesn't move, the light, except to shift in the way that light does as he closes the distance between himself and it, to spread a little further over the walls, picking out beads of condensation and rivulets of dark water. He reaches a hand forward, letting his fingertips lead him toward it, listening intently for the sound of an angel's guttural noises—and then he feels something soft and cool, pliant, and stops.

 

            He straightens. Leans into the light.

 

            It's a fungus. Only two or three shingles, planted flush against the cave wall, a soft pale color not unlike the color of his own hands, beneath the blood, the mud, the matter. The light touches it barely, gently, from up ahead.

 

            Cas turns his face toward it and sees.

 

            Two hundred feet forward, maybe less, the cave lifts, comes to a cliff-edge; a hundred feet above, the stone breaks.

 

            Beyond it is the sky.

 

            Something hot seems to break loose in some deep chamber of Cas' chest; something seems to detach and slide sideways in his head; it's as if he's coming awake, and suddenly he feels—everything—too much—

 

            He looks down at his right hand in the light filtering in and sees for the first time every line of his palm outlined in blood, and something shriveled and gray stuck fast to the cuff of his sleeve.

 

            There is nothing in his stomach to vomit up, but his body does it anyway, hot, stinging acid, and before the stench of bile can reach his nose Cas is running, stumbling, toward that miraculous wall, that miraculous sky, hears himself beginning to cry, feels his bones pulling in and collapsing, remembering in a rush the sounds of the blood in Dean's throat and Sam's far-off distant screams—

 

            He has to get out.

 

            It's right here, right above his head—he stumbles into the wall, hands slip-sliding over its surface, crumpling to the ground, all the weight of it rushing in like an avalanche across his shoulders.

 

He presses his hands to the rock and he breathes in great, gulping sobs, unable to steady himself in the pale, thin light that filters down from above. His fingers are nearly black, darkly stained with gore and meat and mud; one of his fingers crooks oddly at the knuckle as though broken. He had not even noticed. His breath shudders from his lungs, uncontrolled, as though his chest has been crushed, and he sways back onto his feet. He stumbles, braces his hands against the rock, and tilts his head up towards the sky. The fresh air is sharp in his throat, too clean, unpalatable. There is rain, light and cool, upon his upturned face.

 

Cas reaches up towards the light. He slides his hands across the cold, wet stone in search of a crevice to help him climb, a jutting rock, a foothold.

 

He moves, staggering, desperate, drunk on sunlight, the length of the rock wall, his head tilted up to scan the rock. The wall is uneven but worn smooth by rainwater, leaving little in the way of handholds or crevices in which to plant his hands and feet to climb, except—there.

 

Above his head, perhaps three meters high, a narrow ledge, just wide enough for a person to stand, and then higher, the jot of an outcrop upon which to clamber, and climb, and freedom is so close he can feel it as a thickness in his throat. He has made it—all he has to do now is climb.

 

Breathless, unsteady, Cas searches for something on which to boost himself up to the ledge. He stands on tiptoes, reaches up. He plants his boots against the wall, the rubber soles squeaking harshly against the rock before sliding down. To one side, there is a small, uneven lump in the stone, upon which he props the toe of his boot, but it is too small—too slippery—and as soon as he puts any weight upon it, he slips, cracking his knee sharply against the rock. Pain bursts white-hot through the bone, and for a moment, his legs buckle beneath him, shaking, unstable. He breathes through his teeth, swallows hard. He braces his hands against the rock.

 

Cas sets his boot again upon the jut, and he stretches up with his good arm. His fingers scrape across the rock to find purchase, his tattered fingernails squeaking and tearing. He manages to dig two fingers into a crack in the rock, but then something fractures in the wall and he loses his grip, loose stone tumbling down onto his face, stinging in his eyes.

 

He tries again. He stretches further. He curls his hand into a bloody claw, clinging; this time, when he slips and his fingers grate down against the uneven rock, there is the sharp, shooting pain of a fingernail being raggedly ripped loose.

 

Cas’ breath bursts out in a short, ugly noise, a sob bottlenecking in his throat, and he tries again. Again—again.

 

He braces a foot against the wall and he slips and his hands slide against the rock until his palms sting and there is fresh, new, hot blood there, and he is breathless, chest heaving, something hot and ugly and awful constricting in his chest. He scratches and scrapes and claws at the wall, and he leaves shallow gouges in the mud but makes no real impact. Another fingernail is ripped off, hangs limp and bloody from a mangled cuticle. His heart is pounding within his skull. His hands are shaking. There is blood dripping from his fingers and he breathes ragged and he can’t get out. He can’t reach it alone.

 

Slowly, Cas turns his head towards the tunnel at his back.

 

The noise of Sam's screaming behind him has long since stopped. There is only the dull, empty hush of the caves at his back, silence broken by the slow drip of stagnant water, by the whisper of voices. Not so distant, now.

 

Cas lifts his head to look at the ledge above, several feet beyond his grasp. He looks up at the sky beyond the cave’s mouth—pale with the approaching twilight, wisps of grey cloud. He is far enough below the opening that when he breathes, he tastes only the thick, cloying damp of the caves and the blood on his teeth.

 

“Please,” he says, only a whisper. He doesn’t mean to say it—an old habit, gazing up at the open sky. His voice is thick, strangled, in his throat. “Father—please.”

 

Nearer now, the voices of the angels are building from a murmur to a rattling war-cry, a feverish cacophony of unintelligible alien sound, clicking and cicada-screech and half-discordant song in echoes, as they come.

 

Cas rests his hand on the wall, his fingers falling into the grooves scratched raw by his desperate clawing. He finds shreds of his fingernails embedded in the mud and rock, his blood smeared across the stone as of clumsy, child-like finger-painting. His breath judders unevenly in his throat, fear finding him even as he tries to stay calm. “Father?” he says again, small, scared.

 

He doesn’t know why he thinks God would show up now—why he would leave the entirety of heaven to be gutted and burned to the ground, his angels plummeting and burning and crash-landing, fleshless and desperate and blind, to crawl in the mud, but still come through for Castiel. Gomorrah was a gentler fate than what Castiel’s hands wrought. It’s desperation, not faith, that inspires him now.

 

Cas turns back to face the tunnel. In a way, he is almost relieved. There’s no way out of the caves, back to the surface. He has died before, of course, but never of thirst, or starvation. As he understands it, those are slow and agonizing ways to go. Perhaps it is better to die this way—bloody, fighting, glorious.

 

Reluctantly, his mind returns to Sue Harrison, her noose.

 

He doesn’t want to die.

 

At last, finally, they come, cascading and spilling and seething out of the dark, on the dank rock ceiling, on the walls, their claws and fingernails and talons and toes skittering sharply against the stone. They are illuminated by the faint, ghoulish light of their cracked, flayed, slime-slick skin—enough light by which to see the sunken black caverns of their molten eyes; enough to see blood and raw shreds of meat dripping from their bodies. Their hands. Their mouths.

 

Cas swallows thickly.

 

There are more of them than he has seen before—too many. He counts ten, eleven, but they scramble over each other and their limbs twist together and he can’t keep track, but he knows there are too many. With his back against the wall, at least they won’t be able to surround him. If only he could retreat to a narrow space—take them out one by one. He needs a weapon. A rock, or the climbing axe he left behind with Sam.

 

He takes a step backwards, and loose stone skitters dully across the floor, disturbed by his boot.

 

He freezes.

 

On the ceiling and walls and in the mud, the angels become still. Listening.

 

Cas flexes his empty hands at his sides.

 

At once, they erupt.

 

They leap at him, snarling, and Cas dodges backwards out of one angel’s path, lets it crash hard against the floor where it then wheels on him, but he has no time to focus on it as he is ducking the slash of a second razor-sharp wing that slams hard into the rock wall where his head should have been. He grabs the wing at the elbow above his head, shoves up hard until the joint crunches out of alignment, and then as the angel lets out an agonised, rattling scream beside his head, the next two come, slicing at him with fleshless fingers like knives. He hurls a graceless punch at one’s abdomen, knocks it off balance, and then another lands on him, heavy. He is shoved back against the wall.

 

The air is crushed from his lungs, and he is blinded by the searing rush of pain from his bad shoulder, gasping, and then a shard of broken bone jutting from an angel’s mutilated arm catches his hip, and another is going for his eyes, and he throws his arms up protectively in front of his face. He ducks down to flip their weight off until they crash against the rock, but as it is scrambling back up and Cas is regaining his balance to stamp on its skull, another gets hold of him, nails and bone digging into his back, and then gore-slick claws slide and hook into his open mouth. There is blood, hot and thick on his tongue.

 

Cas chokes, retches, and he reels back to slam himself—and it—hard against the wall. It screams and its hands jerk free, ripping through the inside of his mouth and out through his cheek, and then slips from his shoulders. He lunges to try and get past them, to get space to manoeuvre and fight, but something has got hold of his ankles and he staggers, nearly falls. His pulse is thunderous within his ears and his mouth is full of blood and meat. He spits, gags, and then the next angel dives at him, screaming.

 

He only just gets his hands up in time to stop it from tearing his throat out—gets one hand around its jaw, one hand on its face—and his thumb is curling into the crusty, blackened eye socket for leverage and he tries to push it back. It’s stronger than he is, and his bad shoulder is weakened, pain throbbing hotly through his entire arm until he can’t feel his fingertips. He tightens his fingers on its jaw, tries to snap its neck, but his arms are shaking—exhaustion and panic snapping like an animal within his chest—and then something crashes hard into him from behind, and his legs buckle.

 

He hits the ground hard. Rolls himself over, kicks out the leg of one angel, scrambles away backwards and backwards as the angels swarm around him, screeching and slashing out at him, jostling for position as they loom closer.

 

Cas kicks out desperately, catches one in the face with a dull _thunk_ , and his fingers scrabble frantically for purchase on the floor, for a rock or bone or anything he could wield in defense—and then one wing slams down against his upper leg and impales the meat of his thigh. There is a hot flash of searing pain so fierce that it stoppers up his throat and he can’t even scream, and then another angel pins his outstretched arm before he can find any weapon and he hears, distantly, his elbow crunch beneath its grip. Another surges in, digs claws into the front of his jacket and starts tearing at the fabric.

 

Cas jerks, terror rising in his throat as a scream, and he twists to get free but the angels do not let go, and the pressure on his elbow is too much and he can hear it—the crunch, the sickening pop, the slick, wet noise—and his ears are ringing shrilly with the sound coming from his own mouth, a noise that echoes from every black expanse of rock, and his vision is juddering darkly at the edges. He stops screaming only long enough for bile to pitch up hotly into his throat, and then, through the bloody haze, he sees the spray of blood across the first angel’s face. He sees his arm, palm-down in the mud, trodden underfoot, and then kicked carelessly away. There is a strange, electric tingle through his palm; it makes his fingers spasm beyond his control. On the far side of the cavern, his arm—his hand—is still.

 

An angel crawls towards him. It steps on his wrist. From a distance, he hears the bone crunch. His fingers are still tingling.

 

Cas sags against the ground. He stops moving.

 

The blinding-white agony has abated. He can feel his pulse in his throat, and his head throbs with it. His vision swims as the angels close in around him, blackened and broken teeth softly chattering, a low vibrating sound in their throats. He looks across their mangled, blackened, open jaws, the alien tilting of their large, bloated heads. The nearest angel straddles him, mutilated hands and feet and distended wings cracking against the rock either side of his body, and its enormous, bulbous head sways on its thin neck as it tracks down his body to his sternum. With gentleness he has not yet seen from them, it nudges aside the tatters of Cas’ ripped jacket. It curls two claws into the fabric of his T-shirt and tears. The cotton splits easily against its blade-sharp fingers of bone.

 

In the faint light afforded from their skin and the sliver of the sky overhead, Cas sees his own bare chest—his skin bruise-peppered, tacky with dried blood from the injuries to his side and his hip, his ribcage heaving with every breath.

 

The first angel’s head cants left and right as though appraising, uncertain. There is black, rotten meat hanging between what is left of its teeth; up this close, the stench is putrid, overwhelming. Cas heaves, nausea rolling in his gut, and he tries to pull away, but he can’t move. The shard of wing-bone impaled through his thigh holds him still.

 

The angel clicks, chatters, a low vibration of discordant melody in the back of its throat, and its fingers drag slowly over Cas’ sternum. He can his feel his heart bucking wildly in his chest, almost feels his pulse against their nails, and he swallows around the panic, steels himself for what is to come. He knows better than to hope it will be quick.

 

The tip of the claw carves a thin, shallow line through his skin, blood welling to the surface—Cas stifles a noise behind his teeth, the backs of his eyes burning with tears—and then the angel stops. It recoils, makes a noise with three voices that tangles over itself, something harsh and hateful that Cas cannot interpret as it builds into a screech, and it scuttles backwards away from him. The angel with its claws pushed through the inside of Cas’ elbow to hold him still jerks away, pulling its fingers free with a blood-wet, bone-scraping sound. The line of its mutilated spine undulates unevenly, a jerking, unsteady pitching, as of someone retching, and it scrambles backwards, many limbs scuttling and scattering against the rock.

 

A hiss rises in its throat, and it is picked up by the other angels around him, who suddenly now seethe and surge away, clamoring to be away. They climb the walls and the ceiling to turn their empty, blackened eye sockets towards him, blind but baleful, from a safe distance.

 

Cas doesn’t understand. He lies flat on his back in the mud and he stares back up at them, breathing ragged. Slowly, he lifts his head. One leg shifts, the heel of his boot scraping against the stone, but the sound of it doesn’t incite them into fresh violence as he had expected; if anything, it startles them. They chatter and shriek, their unsteady, strident music warbling in their throats, and then they scatter.

 

“Wait,” Cas says, and he is near voiceless, his words a desperate rasp. “Wait.”

 

A few angels linger, huddled like grotesque gargoyles on the ceiling, their spines twisting perversely as they crawl backwards across the rock away from him. With an effort, Cas hauls himself forwards to sit upright. His mangled arm drags along the ground. There is a stub of bone somewhere; it makes a noise like a nail over rust. Blood spreads from the wound in his leg, warm and thick and slow: missed the artery.

 

Cas hauls himself to his feet, staggering upright, his legs giving out beneath him. “Wait,” he says again. “Please—”

 

The angels pause, staring down at him with hatred. Cas is unsteady, shaking like static. He braces a hand against the wall of the cave and he leans heavily upon it, his breath shuddering from his throat.

 

When he finds the words, they come out small, scared. “Please,” he says, and his voice cracks. “Kill me. Please—kill me.”

 

The angels are silent for a long beat, unmoving. Then they turn, and they crawl back the way they came. They leave him.

 

He stares after them into the dark until his eyes ache and all sound of them is gone. No clicking, no singing, no bloodthirsty Enochian murmurings. Only silence, the caves thick and humming with it, and far beyond that, through the hole to the sky, birdsong. Alone, a mile underground, without escape. Cas feels the knowledge tighten in his throat until he cannot breathe around it.

 

He turns, slowly, and he looks back at the cliff-face.

 

Step by wobbling, shivering step, Cas returns to the wall. His pulse throbs within his skull, in his ears, behind his eyes. Black spots pop and bloom at the edges of his vision. He struggles to catch his breath. He lifts his head to look at the ledge cut into the cave wall, several feet out of reach. Beyond it, the green of the crowns of the pines, rain-grey clouds. From here, the sky above his head spans a space no greater than the palm of his hand.

 

It's so close. He is breathing it. He cannot get to it.

 

Cas’ head drops into his chest. He sags against the wall, pressing his face against the wet stone, and for a moment, he just breathes. Slowly, his fingers drag down the rock and fall to hang, limp, useless, at his side.

 

At last, he sinks to his knees in the mud and stagnant water.

 

He is left there, alone, with it all.

 

The rain on his face. The sunlight above.

 

The blood on his skin.


End file.
